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Merge crypto changes from android-4.19.79-95 into msm-4.19

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Conflicts:
	block/blk-merge.c
	drivers/scsi/ufs/ufs-qcom.c
	drivers/scsi/ufs/ufshcd.c
	drivers/scsi/ufs/ufshcd.h
	fs/ext4/inode.c
	fs/f2fs/data.c
	include/linux/fscrypt.h

Change-Id: Id3b033dbc5886ddb83f235ff80e19755d2b962e2
Signed-off-by: Blagovest Kolenichev <bkolenichev@codeaurora.org>
Signed-off-by: Neeraj Soni <neersoni@codeaurora.org>
This commit is contained in:
Blagovest Kolenichev 2020-04-20 05:51:31 -07:00
commit f1598eab74
65 changed files with 7480 additions and 1248 deletions
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183
Documentation/block/inline-encryption.rst Normal file
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@ -0,0 +1,183 @@
.. SPDX-License-Identifier: GPL-2.0
=================
Inline Encryption
=================
Objective
=========
We want to support inline encryption (IE) in the kernel.
To allow for testing, we also want a crypto API fallback when actual
IE hardware is absent. We also want IE to work with layered devices
like dm and loopback (i.e. we want to be able to use the IE hardware
of the underlying devices if present, or else fall back to crypto API
en/decryption).
Constraints and notes
=====================
- IE hardware have a limited number of "keyslots" that can be programmed
with an encryption context (key, algorithm, data unit size, etc.) at any time.
One can specify a keyslot in a data request made to the device, and the
device will en/decrypt the data using the encryption context programmed into
that specified keyslot. When possible, we want to make multiple requests with
the same encryption context share the same keyslot.
- We need a way for filesystems to specify an encryption context to use for
en/decrypting a struct bio, and a device driver (like UFS) needs to be able
to use that encryption context when it processes the bio.
- We need a way for device drivers to expose their capabilities in a unified
way to the upper layers.
Design
======
We add a struct bio_crypt_ctx to struct bio that can represent an
encryption context, because we need to be able to pass this encryption
context from the FS layer to the device driver to act upon.
While IE hardware works on the notion of keyslots, the FS layer has no
knowledge of keyslots - it simply wants to specify an encryption context to
use while en/decrypting a bio.
We introduce a keyslot manager (KSM) that handles the translation from
encryption contexts specified by the FS to keyslots on the IE hardware.
This KSM also serves as the way IE hardware can expose their capabilities to
upper layers. The generic mode of operation is: each device driver that wants
to support IE will construct a KSM and set it up in its struct request_queue.
Upper layers that want to use IE on this device can then use this KSM in
the device's struct request_queue to translate an encryption context into
a keyslot. The presence of the KSM in the request queue shall be used to mean
that the device supports IE.
On the device driver end of the interface, the device driver needs to tell the
KSM how to actually manipulate the IE hardware in the device to do things like
programming the crypto key into the IE hardware into a particular keyslot. All
this is achieved through the :c:type:`struct keyslot_mgmt_ll_ops` that the
device driver passes to the KSM when creating it.
It uses refcounts to track which keyslots are idle (either they have no
encryption context programmed, or there are no in-flight struct bios
referencing that keyslot). When a new encryption context needs a keyslot, it
tries to find a keyslot that has already been programmed with the same
encryption context, and if there is no such keyslot, it evicts the least
recently used idle keyslot and programs the new encryption context into that
one. If no idle keyslots are available, then the caller will sleep until there
is at least one.
Blk-crypto
==========
The above is sufficient for simple cases, but does not work if there is a
need for a crypto API fallback, or if we are want to use IE with layered
devices. To these ends, we introduce blk-crypto. Blk-crypto allows us to
present a unified view of encryption to the FS (so FS only needs to specify
an encryption context and not worry about keyslots at all), and blk-crypto
can decide whether to delegate the en/decryption to IE hardware or to the
crypto API. Blk-crypto maintains an internal KSM that serves as the crypto
API fallback.
Blk-crypto needs to ensure that the encryption context is programmed into the
"correct" keyslot manager for IE. If a bio is submitted to a layered device
that eventually passes the bio down to a device that really does support IE, we
want the encryption context to be programmed into a keyslot for the KSM of the
device with IE support. However, blk-crypto does not know a priori whether a
particular device is the final device in the layering structure for a bio or
not. So in the case that a particular device does not support IE, since it is
possibly the final destination device for the bio, if the bio requires
encryption (i.e. the bio is doing a write operation), blk-crypto must fallback
to the crypto API *before* sending the bio to the device.
Blk-crypto ensures that:
- The bio's encryption context is programmed into a keyslot in the KSM of the
request queue that the bio is being submitted to (or the crypto API fallback
KSM if the request queue doesn't have a KSM), and that the ``processing_ksm``
in the ``bi_crypt_context`` is set to this KSM
- That the bio has its own individual reference to the keyslot in this KSM.
Once the bio passes through blk-crypto, its encryption context is programmed
in some KSM. The "its own individual reference to the keyslot" ensures that
keyslots can be released by each bio independently of other bios while
ensuring that the bio has a valid reference to the keyslot when, for e.g., the
crypto API fallback KSM in blk-crypto performs crypto on the device's behalf.
The individual references are ensured by increasing the refcount for the
keyslot in the ``processing_ksm`` when a bio with a programmed encryption
context is cloned.
What blk-crypto does on bio submission
--------------------------------------
**Case 1:** blk-crypto is given a bio with only an encryption context that hasn't
been programmed into any keyslot in any KSM (for e.g. a bio from the FS).
In this case, blk-crypto will program the encryption context into the KSM of the
request queue the bio is being submitted to (and if this KSM does not exist,
then it will program it into blk-crypto's internal KSM for crypto API
fallback). The KSM that this encryption context was programmed into is stored
as the ``processing_ksm`` in the bio's ``bi_crypt_context``.
**Case 2:** blk-crypto is given a bio whose encryption context has already been
programmed into a keyslot in the *crypto API fallback* KSM.
In this case, blk-crypto does nothing; it treats the bio as not having
specified an encryption context. Note that we cannot do here what we will do
in Case 3 because we would have already encrypted the bio via the crypto API
by this point.
**Case 3:** blk-crypto is given a bio whose encryption context has already been
programmed into a keyslot in some KSM (that is *not* the crypto API fallback
KSM).
In this case, blk-crypto first releases that keyslot from that KSM and then
treats the bio as in Case 1.
This way, when a device driver is processing a bio, it can be sure that
the bio's encryption context has been programmed into some KSM (either the
device driver's request queue's KSM, or blk-crypto's crypto API fallback KSM).
It then simply needs to check if the bio's processing_ksm is the device's
request queue's KSM. If so, then it should proceed with IE. If not, it should
simply do nothing with respect to crypto, because some other KSM (perhaps the
blk-crypto crypto API fallback KSM) is handling the en/decryption.
Blk-crypto will release the keyslot that is being held by the bio (and also
decrypt it if the bio is using the crypto API fallback KSM) once
``bio_remaining_done`` returns true for the bio.
Layered Devices
===============
Layered devices that wish to support IE need to create their own keyslot
manager for their request queue, and expose whatever functionality they choose.
When a layered device wants to pass a bio to another layer (either by
resubmitting the same bio, or by submitting a clone), it doesn't need to do
anything special because the bio (or the clone) will once again pass through
blk-crypto, which will work as described in Case 3. If a layered device wants
for some reason to do the IO by itself instead of passing it on to a child
device, but it also chose to expose IE capabilities by setting up a KSM in its
request queue, it is then responsible for en/decrypting the data itself. In
such cases, the device can choose to call the blk-crypto function
``blk_crypto_fallback_to_kernel_crypto_api`` (TODO: Not yet implemented), which will
cause the en/decryption to be done via the crypto API fallback.
Future Optimizations for layered devices
========================================
Creating a keyslot manager for the layered device uses up memory for each
keyslot, and in general, a layered device (like dm-linear) merely passes the
request on to a "child" device, so the keyslots in the layered device itself
might be completely unused. We can instead define a new type of KSM; the
"passthrough KSM", that layered devices can use to let blk-crypto know that
this layered device *will* pass the bio to some child device (and hence
through blk-crypto again, at which point blk-crypto can program the encryption
context, instead of programming it into the layered device's KSM). Again, if
the device "lies" and decides to do the IO itself instead of passing it on to
a child device, it is responsible for doing the en/decryption (and can choose
to call ``blk_crypto_fallback_to_kernel_crypto_api``). Another use case for the
"passthrough KSM" is for IE devices that want to manage their own keyslots/do
not have a limited number of keyslots.

790
Documentation/filesystems/fscrypt.rst
View file

@ -72,6 +72,9 @@ Online attacks
fscrypt (and storage encryption in general) can only provide limited
protection, if any at all, against online attacks. In detail:
Side-channel attacks
~~~~~~~~~~~~~~~~~~~~
fscrypt is only resistant to side-channel attacks, such as timing or
electromagnetic attacks, to the extent that the underlying Linux
Cryptographic API algorithms are. If a vulnerable algorithm is used,
@ -80,29 +83,90 @@ attacker to mount a side channel attack against the online system.
Side channel attacks may also be mounted against applications
consuming decrypted data.
After an encryption key has been provided, fscrypt is not designed to
hide the plaintext file contents or filenames from other users on the
same system, regardless of the visibility of the keyring key.
Instead, existing access control mechanisms such as file mode bits,
POSIX ACLs, LSMs, or mount namespaces should be used for this purpose.
Also note that as long as the encryption keys are *anywhere* in
memory, an online attacker can necessarily compromise them by mounting
a physical attack or by exploiting any kernel security vulnerability
which provides an arbitrary memory read primitive.
Unauthorized file access
~~~~~~~~~~~~~~~~~~~~~~~~
While it is ostensibly possible to "evict" keys from the system,
recently accessed encrypted files will remain accessible at least
until the filesystem is unmounted or the VFS caches are dropped, e.g.
using ``echo 2 > /proc/sys/vm/drop_caches``. Even after that, if the
RAM is compromised before being powered off, it will likely still be
possible to recover portions of the plaintext file contents, if not
some of the encryption keys as well. (Since Linux v4.12, all
in-kernel keys related to fscrypt are sanitized before being freed.
However, userspace would need to do its part as well.)
After an encryption key has been added, fscrypt does not hide the
plaintext file contents or filenames from other users on the same
system. Instead, existing access control mechanisms such as file mode
bits, POSIX ACLs, LSMs, or namespaces should be used for this purpose.
Currently, fscrypt does not prevent a user from maliciously providing
an incorrect key for another user's existing encrypted files. A
protection against this is planned.
(For the reasoning behind this, understand that while the key is
added, the confidentiality of the data, from the perspective of the
system itself, is *not* protected by the mathematical properties of
encryption but rather only by the correctness of the kernel.
Therefore, any encryption-specific access control checks would merely
be enforced by kernel *code* and therefore would be largely redundant
with the wide variety of access control mechanisms already available.)
Kernel memory compromise
~~~~~~~~~~~~~~~~~~~~~~~~
An attacker who compromises the system enough to read from arbitrary
memory, e.g. by mounting a physical attack or by exploiting a kernel
security vulnerability, can compromise all encryption keys that are
currently in use.
However, fscrypt allows encryption keys to be removed from the kernel,
which may protect them from later compromise.
In more detail, the FS_IOC_REMOVE_ENCRYPTION_KEY ioctl (or the
FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS ioctl) can wipe a master
encryption key from kernel memory. If it does so, it will also try to
evict all cached inodes which had been "unlocked" using the key,
thereby wiping their per-file keys and making them once again appear
"locked", i.e. in ciphertext or encrypted form.
However, these ioctls have some limitations:
- Per-file keys for in-use files will *not* be removed or wiped.
Therefore, for maximum effect, userspace should close the relevant
encrypted files and directories before removing a master key, as
well as kill any processes whose working directory is in an affected
encrypted directory.
- The kernel cannot magically wipe copies of the master key(s) that
userspace might have as well. Therefore, userspace must wipe all
copies of the master key(s) it makes as well; normally this should
be done immediately after FS_IOC_ADD_ENCRYPTION_KEY, without waiting
for FS_IOC_REMOVE_ENCRYPTION_KEY. Naturally, the same also applies
to all higher levels in the key hierarchy. Userspace should also
follow other security precautions such as mlock()ing memory
containing keys to prevent it from being swapped out.
- In general, decrypted contents and filenames in the kernel VFS
caches are freed but not wiped. Therefore, portions thereof may be
recoverable from freed memory, even after the corresponding key(s)
were wiped. To partially solve this, you can set
CONFIG_PAGE_POISONING=y in your kernel config and add page_poison=1
to your kernel command line. However, this has a performance cost.
- Secret keys might still exist in CPU registers, in crypto
accelerator hardware (if used by the crypto API to implement any of
the algorithms), or in other places not explicitly considered here.
Limitations of v1 policies
~~~~~~~~~~~~~~~~~~~~~~~~~~
v1 encryption policies have some weaknesses with respect to online
attacks:
- There is no verification that the provided master key is correct.
Therefore, a malicious user can temporarily associate the wrong key
with another user's encrypted files to which they have read-only
access. Because of filesystem caching, the wrong key will then be
used by the other user's accesses to those files, even if the other
user has the correct key in their own keyring. This violates the
meaning of "read-only access".
- A compromise of a per-file key also compromises the master key from
which it was derived.
- Non-root users cannot securely remove encryption keys.
All the above problems are fixed with v2 encryption policies. For
this reason among others, it is recommended to use v2 encryption
policies on all new encrypted directories.
Key hierarchy
=============
@ -123,11 +187,52 @@ appropriate master key. There can be any number of master keys, each
of which protects any number of directory trees on any number of
filesystems.
Userspace should generate master keys either using a cryptographically
secure random number generator, or by using a KDF (Key Derivation
Function). Note that whenever a KDF is used to "stretch" a
lower-entropy secret such as a passphrase, it is critical that a KDF
designed for this purpose be used, such as scrypt, PBKDF2, or Argon2.
Master keys must be real cryptographic keys, i.e. indistinguishable
from random bytestrings of the same length. This implies that users
**must not** directly use a password as a master key, zero-pad a
shorter key, or repeat a shorter key. Security cannot be guaranteed
if userspace makes any such error, as the cryptographic proofs and
analysis would no longer apply.
Instead, users should generate master keys either using a
cryptographically secure random number generator, or by using a KDF
(Key Derivation Function). The kernel does not do any key stretching;
therefore, if userspace derives the key from a low-entropy secret such
as a passphrase, it is critical that a KDF designed for this purpose
be used, such as scrypt, PBKDF2, or Argon2.
Key derivation function
-----------------------
With one exception, fscrypt never uses the master key(s) for
encryption directly. Instead, they are only used as input to a KDF
(Key Derivation Function) to derive the actual keys.
The KDF used for a particular master key differs depending on whether
the key is used for v1 encryption policies or for v2 encryption
policies. Users **must not** use the same key for both v1 and v2
encryption policies. (No real-world attack is currently known on this
specific case of key reuse, but its security cannot be guaranteed
since the cryptographic proofs and analysis would no longer apply.)
For v1 encryption policies, the KDF only supports deriving per-file
encryption keys. It works by encrypting the master key with
AES-128-ECB, using the file's 16-byte nonce as the AES key. The
resulting ciphertext is used as the derived key. If the ciphertext is
longer than needed, then it is truncated to the needed length.
For v2 encryption policies, the KDF is HKDF-SHA512. The master key is
passed as the "input keying material", no salt is used, and a distinct
"application-specific information string" is used for each distinct
key to be derived. For example, when a per-file encryption key is
derived, the application-specific information string is the file's
nonce prefixed with "fscrypt\\0" and a context byte. Different
context bytes are used for other types of derived keys.
HKDF-SHA512 is preferred to the original AES-128-ECB based KDF because
HKDF is more flexible, is nonreversible, and evenly distributes
entropy from the master key. HKDF is also standardized and widely
used by other software, whereas the AES-128-ECB based KDF is ad-hoc.
Per-file keys
-------------
@ -138,29 +243,9 @@ files doesn't map to the same ciphertext, or vice versa. In most
cases, fscrypt does this by deriving per-file keys. When a new
encrypted inode (regular file, directory, or symlink) is created,
fscrypt randomly generates a 16-byte nonce and stores it in the
inode's encryption xattr. Then, it uses a KDF (Key Derivation
Function) to derive the file's key from the master key and nonce.
The Adiantum encryption mode (see `Encryption modes and usage`_) is
special, since it accepts longer IVs and is suitable for both contents
and filenames encryption. For it, a "direct key" option is offered
where the file's nonce is included in the IVs and the master key is
used for encryption directly. This improves performance; however,
users must not use the same master key for any other encryption mode.
Below, the KDF and design considerations are described in more detail.
The current KDF works by encrypting the master key with AES-128-ECB,
using the file's nonce as the AES key. The output is used as the
derived key. If the output is longer than needed, then it is
truncated to the needed length.
Note: this KDF meets the primary security requirement, which is to
produce unique derived keys that preserve the entropy of the master
key, assuming that the master key is already a good pseudorandom key.
However, it is nonstandard and has some problems such as being
reversible, so it is generally considered to be a mistake! It may be
replaced with HKDF or another more standard KDF in the future.
inode's encryption xattr. Then, it uses a KDF (as described in `Key
derivation function`_) to derive the file's key from the master key
and nonce.
Key derivation was chosen over key wrapping because wrapped keys would
require larger xattrs which would be less likely to fit in-line in the
@ -171,10 +256,51 @@ alternative master keys or to support rotating master keys. Instead,
the master keys may be wrapped in userspace, e.g. as is done by the
`fscrypt <https://github.com/google/fscrypt>`_ tool.
Including the inode number in the IVs was considered. However, it was
rejected as it would have prevented ext4 filesystems from being
resized, and by itself still wouldn't have been sufficient to prevent
the same key from being directly reused for both XTS and CTS-CBC.
DIRECT_KEY policies
-------------------
The Adiantum encryption mode (see `Encryption modes and usage`_) is
suitable for both contents and filenames encryption, and it accepts
long IVs --- long enough to hold both an 8-byte logical block number
and a 16-byte per-file nonce. Also, the overhead of each Adiantum key
is greater than that of an AES-256-XTS key.
Therefore, to improve performance and save memory, for Adiantum a
"direct key" configuration is supported. When the user has enabled
this by setting FSCRYPT_POLICY_FLAG_DIRECT_KEY in the fscrypt policy,
per-file keys are not used. Instead, whenever any data (contents or
filenames) is encrypted, the file's 16-byte nonce is included in the
IV. Moreover:
- For v1 encryption policies, the encryption is done directly with the
master key. Because of this, users **must not** use the same master
key for any other purpose, even for other v1 policies.
- For v2 encryption policies, the encryption is done with a per-mode
key derived using the KDF. Users may use the same master key for
other v2 encryption policies.
IV_INO_LBLK_64 policies
-----------------------
When FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 is set in the fscrypt policy,
the encryption keys are derived from the master key, encryption mode
number, and filesystem UUID. This normally results in all files
protected by the same master key sharing a single contents encryption
key and a single filenames encryption key. To still encrypt different
files' data differently, inode numbers are included in the IVs.
Consequently, shrinking the filesystem may not be allowed.
This format is optimized for use with inline encryption hardware
compliant with the UFS or eMMC standards, which support only 64 IV
bits per I/O request and may have only a small number of keyslots.
Key identifiers
---------------
For master keys used for v2 encryption policies, a unique 16-byte "key
identifier" is also derived using the KDF. This value is stored in
the clear, since it is needed to reliably identify the key itself.
Encryption modes and usage
==========================
@ -192,8 +318,9 @@ If unsure, you should use the (AES-256-XTS, AES-256-CTS-CBC) pair.
AES-128-CBC was added only for low-powered embedded devices with
crypto accelerators such as CAAM or CESA that do not support XTS. To
use AES-128-CBC, CONFIG_CRYPTO_SHA256 (or another SHA-256
implementation) must be enabled so that ESSIV can be used.
use AES-128-CBC, CONFIG_CRYPTO_ESSIV and CONFIG_CRYPTO_SHA256 (or
another SHA-256 implementation) must be enabled so that ESSIV can be
used.
Adiantum is a (primarily) stream cipher-based mode that is fast even
on CPUs without dedicated crypto instructions. It's also a true
@ -225,10 +352,17 @@ a little endian number, except that:
is encrypted with AES-256 where the AES-256 key is the SHA-256 hash
of the file's data encryption key.
- In the "direct key" configuration (FS_POLICY_FLAG_DIRECT_KEY set in
the fscrypt_policy), the file's nonce is also appended to the IV.
- With `DIRECT_KEY policies`_, the file's nonce is appended to the IV.
Currently this is only allowed with the Adiantum encryption mode.
- With `IV_INO_LBLK_64 policies`_, the logical block number is limited
to 32 bits and is placed in bits 0-31 of the IV. The inode number
(which is also limited to 32 bits) is placed in bits 32-63.
Note that because file logical block numbers are included in the IVs,
filesystems must enforce that blocks are never shifted around within
encrypted files, e.g. via "collapse range" or "insert range".
Filenames encryption
--------------------
@ -237,10 +371,10 @@ the requirements to retain support for efficient directory lookups and
filenames of up to 255 bytes, the same IV is used for every filename
in a directory.
However, each encrypted directory still uses a unique key; or
alternatively (for the "direct key" configuration) has the file's
nonce included in the IVs. Thus, IV reuse is limited to within a
single directory.
However, each encrypted directory still uses a unique key, or
alternatively has the file's nonce (for `DIRECT_KEY policies`_) or
inode number (for `IV_INO_LBLK_64 policies`_) included in the IVs.
Thus, IV reuse is limited to within a single directory.
With CTS-CBC, the IV reuse means that when the plaintext filenames
share a common prefix at least as long as the cipher block size (16
@ -269,49 +403,80 @@ User API
Setting an encryption policy
----------------------------
FS_IOC_SET_ENCRYPTION_POLICY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The FS_IOC_SET_ENCRYPTION_POLICY ioctl sets an encryption policy on an
empty directory or verifies that a directory or regular file already
has the specified encryption policy. It takes in a pointer to a
:c:type:`struct fscrypt_policy`, defined as follows::
:c:type:`struct fscrypt_policy_v1` or a :c:type:`struct
fscrypt_policy_v2`, defined as follows::
#define FS_KEY_DESCRIPTOR_SIZE 8
struct fscrypt_policy {
#define FSCRYPT_POLICY_V1 0
#define FSCRYPT_KEY_DESCRIPTOR_SIZE 8
struct fscrypt_policy_v1 {
__u8 version;
__u8 contents_encryption_mode;
__u8 filenames_encryption_mode;
__u8 flags;
__u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
__u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
};
#define fscrypt_policy fscrypt_policy_v1
#define FSCRYPT_POLICY_V2 2
#define FSCRYPT_KEY_IDENTIFIER_SIZE 16
struct fscrypt_policy_v2 {
__u8 version;
__u8 contents_encryption_mode;
__u8 filenames_encryption_mode;
__u8 flags;
__u8 __reserved[4];
__u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
};
This structure must be initialized as follows:
- ``version`` must be 0.
- ``version`` must be FSCRYPT_POLICY_V1 (0) if the struct is
:c:type:`fscrypt_policy_v1` or FSCRYPT_POLICY_V2 (2) if the struct
is :c:type:`fscrypt_policy_v2`. (Note: we refer to the original
policy version as "v1", though its version code is really 0.) For
new encrypted directories, use v2 policies.
- ``contents_encryption_mode`` and ``filenames_encryption_mode`` must
be set to constants from ``<linux/fs.h>`` which identify the
encryption modes to use. If unsure, use
FS_ENCRYPTION_MODE_AES_256_XTS (1) for ``contents_encryption_mode``
and FS_ENCRYPTION_MODE_AES_256_CTS (4) for
``filenames_encryption_mode``.
be set to constants from ``<linux/fscrypt.h>`` which identify the
encryption modes to use. If unsure, use FSCRYPT_MODE_AES_256_XTS
(1) for ``contents_encryption_mode`` and FSCRYPT_MODE_AES_256_CTS
(4) for ``filenames_encryption_mode``.
- ``flags`` must contain a value from ``<linux/fs.h>`` which
identifies the amount of NUL-padding to use when encrypting
filenames. If unsure, use FS_POLICY_FLAGS_PAD_32 (0x3).
In addition, if the chosen encryption modes are both
FS_ENCRYPTION_MODE_ADIANTUM, this can contain
FS_POLICY_FLAG_DIRECT_KEY to specify that the master key should be
used directly, without key derivation.
- ``flags`` contains optional flags from ``<linux/fscrypt.h>``:
- ``master_key_descriptor`` specifies how to find the master key in
the keyring; see `Adding keys`_. It is up to userspace to choose a
unique ``master_key_descriptor`` for each master key. The e4crypt
and fscrypt tools use the first 8 bytes of
- FSCRYPT_POLICY_FLAGS_PAD_*: The amount of NUL padding to use when
encrypting filenames. If unsure, use FSCRYPT_POLICY_FLAGS_PAD_32
(0x3).
- FSCRYPT_POLICY_FLAG_DIRECT_KEY: See `DIRECT_KEY policies`_.
- FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64: See `IV_INO_LBLK_64
policies`_. This is mutually exclusive with DIRECT_KEY and is not
supported on v1 policies.
- For v2 encryption policies, ``__reserved`` must be zeroed.
- For v1 encryption policies, ``master_key_descriptor`` specifies how
to find the master key in a keyring; see `Adding keys`_. It is up
to userspace to choose a unique ``master_key_descriptor`` for each
master key. The e4crypt and fscrypt tools use the first 8 bytes of
``SHA-512(SHA-512(master_key))``, but this particular scheme is not
required. Also, the master key need not be in the keyring yet when
FS_IOC_SET_ENCRYPTION_POLICY is executed. However, it must be added
before any files can be created in the encrypted directory.
For v2 encryption policies, ``master_key_descriptor`` has been
replaced with ``master_key_identifier``, which is longer and cannot
be arbitrarily chosen. Instead, the key must first be added using
`FS_IOC_ADD_ENCRYPTION_KEY`_. Then, the ``key_spec.u.identifier``
the kernel returned in the :c:type:`struct fscrypt_add_key_arg` must
be used as the ``master_key_identifier`` in the :c:type:`struct
fscrypt_policy_v2`.
If the file is not yet encrypted, then FS_IOC_SET_ENCRYPTION_POLICY
verifies that the file is an empty directory. If so, the specified
encryption policy is assigned to the directory, turning it into an
@ -327,6 +492,15 @@ policy exactly matches the actual one. If they match, then the ioctl
returns 0. Otherwise, it fails with EEXIST. This works on both
regular files and directories, including nonempty directories.
When a v2 encryption policy is assigned to a directory, it is also
required that either the specified key has been added by the current
user or that the caller has CAP_FOWNER in the initial user namespace.
(This is needed to prevent a user from encrypting their data with
another user's key.) The key must remain added while
FS_IOC_SET_ENCRYPTION_POLICY is executing. However, if the new
encrypted directory does not need to be accessed immediately, then the
key can be removed right away afterwards.
Note that the ext4 filesystem does not allow the root directory to be
encrypted, even if it is empty. Users who want to encrypt an entire
filesystem with one key should consider using dm-crypt instead.
@ -339,7 +513,11 @@ FS_IOC_SET_ENCRYPTION_POLICY can fail with the following errors:
- ``EEXIST``: the file is already encrypted with an encryption policy
different from the one specified
- ``EINVAL``: an invalid encryption policy was specified (invalid
version, mode(s), or flags)
version, mode(s), or flags; or reserved bits were set)
- ``ENOKEY``: a v2 encryption policy was specified, but the key with
the specified ``master_key_identifier`` has not been added, nor does
the process have the CAP_FOWNER capability in the initial user
namespace
- ``ENOTDIR``: the file is unencrypted and is a regular file, not a
directory
- ``ENOTEMPTY``: the file is unencrypted and is a nonempty directory
@ -358,25 +536,79 @@ FS_IOC_SET_ENCRYPTION_POLICY can fail with the following errors:
Getting an encryption policy
----------------------------
The FS_IOC_GET_ENCRYPTION_POLICY ioctl retrieves the :c:type:`struct
fscrypt_policy`, if any, for a directory or regular file. See above
for the struct definition. No additional permissions are required
beyond the ability to open the file.
Two ioctls are available to get a file's encryption policy:
FS_IOC_GET_ENCRYPTION_POLICY can fail with the following errors:
- `FS_IOC_GET_ENCRYPTION_POLICY_EX`_
- `FS_IOC_GET_ENCRYPTION_POLICY`_
The extended (_EX) version of the ioctl is more general and is
recommended to use when possible. However, on older kernels only the
original ioctl is available. Applications should try the extended
version, and if it fails with ENOTTY fall back to the original
version.
FS_IOC_GET_ENCRYPTION_POLICY_EX
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The FS_IOC_GET_ENCRYPTION_POLICY_EX ioctl retrieves the encryption
policy, if any, for a directory or regular file. No additional
permissions are required beyond the ability to open the file. It
takes in a pointer to a :c:type:`struct fscrypt_get_policy_ex_arg`,
defined as follows::
struct fscrypt_get_policy_ex_arg {
__u64 policy_size; /* input/output */
union {
__u8 version;
struct fscrypt_policy_v1 v1;
struct fscrypt_policy_v2 v2;
} policy; /* output */
};
The caller must initialize ``policy_size`` to the size available for
the policy struct, i.e. ``sizeof(arg.policy)``.
On success, the policy struct is returned in ``policy``, and its
actual size is returned in ``policy_size``. ``policy.version`` should
be checked to determine the version of policy returned. Note that the
version code for the "v1" policy is actually 0 (FSCRYPT_POLICY_V1).
FS_IOC_GET_ENCRYPTION_POLICY_EX can fail with the following errors:
- ``EINVAL``: the file is encrypted, but it uses an unrecognized
encryption context format
encryption policy version
- ``ENODATA``: the file is not encrypted
- ``ENOTTY``: this type of filesystem does not implement encryption
- ``ENOTTY``: this type of filesystem does not implement encryption,
or this kernel is too old to support FS_IOC_GET_ENCRYPTION_POLICY_EX
(try FS_IOC_GET_ENCRYPTION_POLICY instead)
- ``EOPNOTSUPP``: the kernel was not configured with encryption
support for this filesystem
support for this filesystem, or the filesystem superblock has not
had encryption enabled on it
- ``EOVERFLOW``: the file is encrypted and uses a recognized
encryption policy version, but the policy struct does not fit into
the provided buffer
Note: if you only need to know whether a file is encrypted or not, on
most filesystems it is also possible to use the FS_IOC_GETFLAGS ioctl
and check for FS_ENCRYPT_FL, or to use the statx() system call and
check for STATX_ATTR_ENCRYPTED in stx_attributes.
FS_IOC_GET_ENCRYPTION_POLICY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The FS_IOC_GET_ENCRYPTION_POLICY ioctl can also retrieve the
encryption policy, if any, for a directory or regular file. However,
unlike `FS_IOC_GET_ENCRYPTION_POLICY_EX`_,
FS_IOC_GET_ENCRYPTION_POLICY only supports the original policy
version. It takes in a pointer directly to a :c:type:`struct
fscrypt_policy_v1` rather than a :c:type:`struct
fscrypt_get_policy_ex_arg`.
The error codes for FS_IOC_GET_ENCRYPTION_POLICY are the same as those
for FS_IOC_GET_ENCRYPTION_POLICY_EX, except that
FS_IOC_GET_ENCRYPTION_POLICY also returns ``EINVAL`` if the file is
encrypted using a newer encryption policy version.
Getting the per-filesystem salt
-------------------------------
@ -392,8 +624,115 @@ generate and manage any needed salt(s) in userspace.
Adding keys
-----------
To provide a master key, userspace must add it to an appropriate
keyring using the add_key() system call (see:
FS_IOC_ADD_ENCRYPTION_KEY
~~~~~~~~~~~~~~~~~~~~~~~~~
The FS_IOC_ADD_ENCRYPTION_KEY ioctl adds a master encryption key to
the filesystem, making all files on the filesystem which were
encrypted using that key appear "unlocked", i.e. in plaintext form.
It can be executed on any file or directory on the target filesystem,
but using the filesystem's root directory is recommended. It takes in
a pointer to a :c:type:`struct fscrypt_add_key_arg`, defined as
follows::
struct fscrypt_add_key_arg {
struct fscrypt_key_specifier key_spec;
__u32 raw_size;
__u32 __reserved[9];
__u8 raw[];
};
#define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR 1
#define FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER 2
struct fscrypt_key_specifier {
__u32 type; /* one of FSCRYPT_KEY_SPEC_TYPE_* */
__u32 __reserved;
union {
__u8 __reserved[32]; /* reserve some extra space */
__u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
__u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
} u;
};
:c:type:`struct fscrypt_add_key_arg` must be zeroed, then initialized
as follows:
- If the key is being added for use by v1 encryption policies, then
``key_spec.type`` must contain FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR, and
``key_spec.u.descriptor`` must contain the descriptor of the key
being added, corresponding to the value in the
``master_key_descriptor`` field of :c:type:`struct
fscrypt_policy_v1`. To add this type of key, the calling process
must have the CAP_SYS_ADMIN capability in the initial user
namespace.
Alternatively, if the key is being added for use by v2 encryption
policies, then ``key_spec.type`` must contain
FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER, and ``key_spec.u.identifier`` is
an *output* field which the kernel fills in with a cryptographic
hash of the key. To add this type of key, the calling process does
not need any privileges. However, the number of keys that can be
added is limited by the user's quota for the keyrings service (see
``Documentation/security/keys/core.rst``).
- ``raw_size`` must be the size of the ``raw`` key provided, in bytes.
- ``raw`` is a variable-length field which must contain the actual
key, ``raw_size`` bytes long.
For v2 policy keys, the kernel keeps track of which user (identified
by effective user ID) added the key, and only allows the key to be
removed by that user --- or by "root", if they use
`FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS`_.
However, if another user has added the key, it may be desirable to
prevent that other user from unexpectedly removing it. Therefore,
FS_IOC_ADD_ENCRYPTION_KEY may also be used to add a v2 policy key
*again*, even if it's already added by other user(s). In this case,
FS_IOC_ADD_ENCRYPTION_KEY will just install a claim to the key for the
current user, rather than actually add the key again (but the raw key
must still be provided, as a proof of knowledge).
FS_IOC_ADD_ENCRYPTION_KEY returns 0 if either the key or a claim to
the key was either added or already exists.
FS_IOC_ADD_ENCRYPTION_KEY can fail with the following errors:
- ``EACCES``: FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR was specified, but the
caller does not have the CAP_SYS_ADMIN capability in the initial
user namespace
- ``EDQUOT``: the key quota for this user would be exceeded by adding
the key
- ``EINVAL``: invalid key size or key specifier type, or reserved bits
were set
- ``ENOTTY``: this type of filesystem does not implement encryption
- ``EOPNOTSUPP``: the kernel was not configured with encryption
support for this filesystem, or the filesystem superblock has not
had encryption enabled on it
Legacy method
~~~~~~~~~~~~~
For v1 encryption policies, a master encryption key can also be
provided by adding it to a process-subscribed keyring, e.g. to a
session keyring, or to a user keyring if the user keyring is linked
into the session keyring.
This method is deprecated (and not supported for v2 encryption
policies) for several reasons. First, it cannot be used in
combination with FS_IOC_REMOVE_ENCRYPTION_KEY (see `Removing keys`_),
so for removing a key a workaround such as keyctl_unlink() in
combination with ``sync; echo 2 > /proc/sys/vm/drop_caches`` would
have to be used. Second, it doesn't match the fact that the
locked/unlocked status of encrypted files (i.e. whether they appear to
be in plaintext form or in ciphertext form) is global. This mismatch
has caused much confusion as well as real problems when processes
running under different UIDs, such as a ``sudo`` command, need to
access encrypted files.
Nevertheless, to add a key to one of the process-subscribed keyrings,
the add_key() system call can be used (see:
``Documentation/security/keys/core.rst``). The key type must be
"logon"; keys of this type are kept in kernel memory and cannot be
read back by userspace. The key description must be "fscrypt:"
@ -401,12 +740,12 @@ followed by the 16-character lower case hex representation of the
``master_key_descriptor`` that was set in the encryption policy. The
key payload must conform to the following structure::
#define FS_MAX_KEY_SIZE 64
#define FSCRYPT_MAX_KEY_SIZE 64
struct fscrypt_key {
u32 mode;
u8 raw[FS_MAX_KEY_SIZE];
u32 size;
__u32 mode;
__u8 raw[FSCRYPT_MAX_KEY_SIZE];
__u32 size;
};
``mode`` is ignored; just set it to 0. The actual key is provided in
@ -418,26 +757,194 @@ with a filesystem-specific prefix such as "ext4:". However, the
filesystem-specific prefixes are deprecated and should not be used in
new programs.
There are several different types of keyrings in which encryption keys
may be placed, such as a session keyring, a user session keyring, or a
user keyring. Each key must be placed in a keyring that is "attached"
to all processes that might need to access files encrypted with it, in
the sense that request_key() will find the key. Generally, if only
processes belonging to a specific user need to access a given
encrypted directory and no session keyring has been installed, then
that directory's key should be placed in that user's user session
keyring or user keyring. Otherwise, a session keyring should be
installed if needed, and the key should be linked into that session
keyring, or in a keyring linked into that session keyring.
Removing keys
-------------
Note: introducing the complex visibility semantics of keyrings here
was arguably a mistake --- especially given that by design, after any
process successfully opens an encrypted file (thereby setting up the
per-file key), possessing the keyring key is not actually required for
any process to read/write the file until its in-memory inode is
evicted. In the future there probably should be a way to provide keys
directly to the filesystem instead, which would make the intended
semantics clearer.
Two ioctls are available for removing a key that was added by
`FS_IOC_ADD_ENCRYPTION_KEY`_:
- `FS_IOC_REMOVE_ENCRYPTION_KEY`_
- `FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS`_
These two ioctls differ only in cases where v2 policy keys are added
or removed by non-root users.
These ioctls don't work on keys that were added via the legacy
process-subscribed keyrings mechanism.
Before using these ioctls, read the `Kernel memory compromise`_
section for a discussion of the security goals and limitations of
these ioctls.
FS_IOC_REMOVE_ENCRYPTION_KEY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The FS_IOC_REMOVE_ENCRYPTION_KEY ioctl removes a claim to a master
encryption key from the filesystem, and possibly removes the key
itself. It can be executed on any file or directory on the target
filesystem, but using the filesystem's root directory is recommended.
It takes in a pointer to a :c:type:`struct fscrypt_remove_key_arg`,
defined as follows::
struct fscrypt_remove_key_arg {
struct fscrypt_key_specifier key_spec;
#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY 0x00000001
#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS 0x00000002
__u32 removal_status_flags; /* output */
__u32 __reserved[5];
};
This structure must be zeroed, then initialized as follows:
- The key to remove is specified by ``key_spec``:
- To remove a key used by v1 encryption policies, set
``key_spec.type`` to FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR and fill
in ``key_spec.u.descriptor``. To remove this type of key, the
calling process must have the CAP_SYS_ADMIN capability in the
initial user namespace.
- To remove a key used by v2 encryption policies, set
``key_spec.type`` to FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER and fill
in ``key_spec.u.identifier``.
For v2 policy keys, this ioctl is usable by non-root users. However,
to make this possible, it actually just removes the current user's
claim to the key, undoing a single call to FS_IOC_ADD_ENCRYPTION_KEY.
Only after all claims are removed is the key really removed.
For example, if FS_IOC_ADD_ENCRYPTION_KEY was called with uid 1000,
then the key will be "claimed" by uid 1000, and
FS_IOC_REMOVE_ENCRYPTION_KEY will only succeed as uid 1000. Or, if
both uids 1000 and 2000 added the key, then for each uid
FS_IOC_REMOVE_ENCRYPTION_KEY will only remove their own claim. Only
once *both* are removed is the key really removed. (Think of it like
unlinking a file that may have hard links.)
If FS_IOC_REMOVE_ENCRYPTION_KEY really removes the key, it will also
try to "lock" all files that had been unlocked with the key. It won't
lock files that are still in-use, so this ioctl is expected to be used
in cooperation with userspace ensuring that none of the files are
still open. However, if necessary, this ioctl can be executed again
later to retry locking any remaining files.
FS_IOC_REMOVE_ENCRYPTION_KEY returns 0 if either the key was removed
(but may still have files remaining to be locked), the user's claim to
the key was removed, or the key was already removed but had files
remaining to be the locked so the ioctl retried locking them. In any
of these cases, ``removal_status_flags`` is filled in with the
following informational status flags:
- ``FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY``: set if some file(s)
are still in-use. Not guaranteed to be set in the case where only
the user's claim to the key was removed.
- ``FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS``: set if only the
user's claim to the key was removed, not the key itself
FS_IOC_REMOVE_ENCRYPTION_KEY can fail with the following errors:
- ``EACCES``: The FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR key specifier type
was specified, but the caller does not have the CAP_SYS_ADMIN
capability in the initial user namespace
- ``EINVAL``: invalid key specifier type, or reserved bits were set
- ``ENOKEY``: the key object was not found at all, i.e. it was never
added in the first place or was already fully removed including all
files locked; or, the user does not have a claim to the key (but
someone else does).
- ``ENOTTY``: this type of filesystem does not implement encryption
- ``EOPNOTSUPP``: the kernel was not configured with encryption
support for this filesystem, or the filesystem superblock has not
had encryption enabled on it
FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS is exactly the same as
`FS_IOC_REMOVE_ENCRYPTION_KEY`_, except that for v2 policy keys, the
ALL_USERS version of the ioctl will remove all users' claims to the
key, not just the current user's. I.e., the key itself will always be
removed, no matter how many users have added it. This difference is
only meaningful if non-root users are adding and removing keys.
Because of this, FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS also requires
"root", namely the CAP_SYS_ADMIN capability in the initial user
namespace. Otherwise it will fail with EACCES.
Getting key status
------------------
FS_IOC_GET_ENCRYPTION_KEY_STATUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The FS_IOC_GET_ENCRYPTION_KEY_STATUS ioctl retrieves the status of a
master encryption key. It can be executed on any file or directory on
the target filesystem, but using the filesystem's root directory is
recommended. It takes in a pointer to a :c:type:`struct
fscrypt_get_key_status_arg`, defined as follows::
struct fscrypt_get_key_status_arg {
/* input */
struct fscrypt_key_specifier key_spec;
__u32 __reserved[6];
/* output */
#define FSCRYPT_KEY_STATUS_ABSENT 1
#define FSCRYPT_KEY_STATUS_PRESENT 2
#define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED 3
__u32 status;
#define FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF 0x00000001
__u32 status_flags;
__u32 user_count;
__u32 __out_reserved[13];
};
The caller must zero all input fields, then fill in ``key_spec``:
- To get the status of a key for v1 encryption policies, set
``key_spec.type`` to FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR and fill
in ``key_spec.u.descriptor``.
- To get the status of a key for v2 encryption policies, set
``key_spec.type`` to FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER and fill
in ``key_spec.u.identifier``.
On success, 0 is returned and the kernel fills in the output fields:
- ``status`` indicates whether the key is absent, present, or
incompletely removed. Incompletely removed means that the master
secret has been removed, but some files are still in use; i.e.,
`FS_IOC_REMOVE_ENCRYPTION_KEY`_ returned 0 but set the informational
status flag FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY.
- ``status_flags`` can contain the following flags:
- ``FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF`` indicates that the key
has added by the current user. This is only set for keys
identified by ``identifier`` rather than by ``descriptor``.
- ``user_count`` specifies the number of users who have added the key.
This is only set for keys identified by ``identifier`` rather than
by ``descriptor``.
FS_IOC_GET_ENCRYPTION_KEY_STATUS can fail with the following errors:
- ``EINVAL``: invalid key specifier type, or reserved bits were set
- ``ENOTTY``: this type of filesystem does not implement encryption
- ``EOPNOTSUPP``: the kernel was not configured with encryption
support for this filesystem, or the filesystem superblock has not
had encryption enabled on it
Among other use cases, FS_IOC_GET_ENCRYPTION_KEY_STATUS can be useful
for determining whether the key for a given encrypted directory needs
to be added before prompting the user for the passphrase needed to
derive the key.
FS_IOC_GET_ENCRYPTION_KEY_STATUS can only get the status of keys in
the filesystem-level keyring, i.e. the keyring managed by
`FS_IOC_ADD_ENCRYPTION_KEY`_ and `FS_IOC_REMOVE_ENCRYPTION_KEY`_. It
cannot get the status of a key that has only been added for use by v1
encryption policies using the legacy mechanism involving
process-subscribed keyrings.
Access semantics
================
@ -500,7 +1007,7 @@ Without the key
Some filesystem operations may be performed on encrypted regular
files, directories, and symlinks even before their encryption key has
been provided:
been added, or after their encryption key has been removed:
- File metadata may be read, e.g. using stat().
@ -565,33 +1072,44 @@ Encryption context
------------------
An encryption policy is represented on-disk by a :c:type:`struct
fscrypt_context`. It is up to individual filesystems to decide where
to store it, but normally it would be stored in a hidden extended
attribute. It should *not* be exposed by the xattr-related system
calls such as getxattr() and setxattr() because of the special
semantics of the encryption xattr. (In particular, there would be
much confusion if an encryption policy were to be added to or removed
from anything other than an empty directory.) The struct is defined
as follows::
fscrypt_context_v1` or a :c:type:`struct fscrypt_context_v2`. It is
up to individual filesystems to decide where to store it, but normally
it would be stored in a hidden extended attribute. It should *not* be
exposed by the xattr-related system calls such as getxattr() and
setxattr() because of the special semantics of the encryption xattr.
(In particular, there would be much confusion if an encryption policy
were to be added to or removed from anything other than an empty
directory.) These structs are defined as follows::
#define FS_KEY_DESCRIPTOR_SIZE 8
#define FS_KEY_DERIVATION_NONCE_SIZE 16
struct fscrypt_context {
u8 format;
#define FSCRYPT_KEY_DESCRIPTOR_SIZE 8
struct fscrypt_context_v1 {
u8 version;
u8 contents_encryption_mode;
u8 filenames_encryption_mode;
u8 flags;
u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
};
Note that :c:type:`struct fscrypt_context` contains the same
information as :c:type:`struct fscrypt_policy` (see `Setting an
encryption policy`_), except that :c:type:`struct fscrypt_context`
also contains a nonce. The nonce is randomly generated by the kernel
and is used to derive the inode's encryption key as described in
`Per-file keys`_.
#define FSCRYPT_KEY_IDENTIFIER_SIZE 16
struct fscrypt_context_v2 {
u8 version;
u8 contents_encryption_mode;
u8 filenames_encryption_mode;
u8 flags;
u8 __reserved[4];
u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
};
The context structs contain the same information as the corresponding
policy structs (see `Setting an encryption policy`_), except that the
context structs also contain a nonce. The nonce is randomly generated
by the kernel and is used as KDF input or as a tweak to cause
different files to be encrypted differently; see `Per-file keys`_ and
`DIRECT_KEY policies`_.
Data path changes
-----------------

1
MAINTAINERS
View file

@ -6013,6 +6013,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt.git
S: Supported
F: fs/crypto/
F: include/linux/fscrypt*.h
F: include/uapi/linux/fscrypt.h
F: Documentation/filesystems/fscrypt.rst
FSI-ATTACHED I2C DRIVER

3
arch/arm64/configs/gki_defconfig
View file

@ -81,6 +81,7 @@ CONFIG_SHADOW_CALL_STACK=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODVERSIONS=y
CONFIG_BLK_INLINE_ENCRYPTION=y
CONFIG_GKI_HACKS_TO_FIX=y
# CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
CONFIG_BINFMT_MISC=m
@ -222,6 +223,7 @@ CONFIG_SCSI=y
CONFIG_BLK_DEV_SD=y
CONFIG_SCSI_UFSHCD=y
CONFIG_SCSI_UFSHCD_PLATFORM=y
CONFIG_SCSI_UFS_CRYPTO=y
CONFIG_MD=y
CONFIG_BLK_DEV_DM=y
CONFIG_DM_CRYPT=y
@ -392,6 +394,7 @@ CONFIG_EXT4_FS_SECURITY=y
CONFIG_F2FS_FS=y
CONFIG_F2FS_FS_SECURITY=y
CONFIG_FS_ENCRYPTION=y
CONFIG_FS_ENCRYPTION_INLINE_CRYPT=y
CONFIG_FS_VERITY=y
CONFIG_FS_VERITY_BUILTIN_SIGNATURES=y
# CONFIG_DNOTIFY is not set

2
arch/x86/configs/gki_defconfig
View file

@ -50,6 +50,7 @@ CONFIG_KPROBES=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODVERSIONS=y
CONFIG_BLK_INLINE_ENCRYPTION=y
CONFIG_GKI_HACKS_TO_FIX=y
# CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
CONFIG_BINFMT_MISC=m
@ -329,6 +330,7 @@ CONFIG_EXT4_ENCRYPTION=y
CONFIG_F2FS_FS=y
CONFIG_F2FS_FS_SECURITY=y
CONFIG_F2FS_FS_ENCRYPTION=y
CONFIG_FS_ENCRYPTION_INLINE_CRYPT=y
CONFIG_FS_VERITY=y
CONFIG_FS_VERITY_BUILTIN_SIGNATURES=y
# CONFIG_DNOTIFY is not set

10
block/Kconfig
View file

@ -200,6 +200,16 @@ config BLK_SED_OPAL
Enabling this option enables users to setup/unlock/lock
Locking ranges for SED devices using the Opal protocol.
config BLK_INLINE_ENCRYPTION
bool "Enable inline encryption support in block layer"
select CRYPTO
select CRYPTO_BLKCIPHER
help
Build the blk-crypto subsystem.
Enabling this lets the block layer handle encryption,
so users can take advantage of inline encryption
hardware if present.
menu "Partition Types"
source "block/partitions/Kconfig"

2
block/Makefile
View file

@ -37,3 +37,5 @@ obj-$(CONFIG_BLK_WBT) += blk-wbt.o
obj-$(CONFIG_BLK_DEBUG_FS) += blk-mq-debugfs.o
obj-$(CONFIG_BLK_DEBUG_FS_ZONED)+= blk-mq-debugfs-zoned.o
obj-$(CONFIG_BLK_SED_OPAL) += sed-opal.o
obj-$(CONFIG_BLK_INLINE_ENCRYPTION) += keyslot-manager.o bio-crypt-ctx.o \
blk-crypto.o

145
block/bio-crypt-ctx.c Normal file
View file

@ -0,0 +1,145 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2019 Google LLC
*/
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/keyslot-manager.h>
static int num_prealloc_crypt_ctxs = 128;
static struct kmem_cache *bio_crypt_ctx_cache;
static mempool_t *bio_crypt_ctx_pool;
int bio_crypt_ctx_init(void)
{
bio_crypt_ctx_cache = KMEM_CACHE(bio_crypt_ctx, 0);
if (!bio_crypt_ctx_cache)
return -ENOMEM;
bio_crypt_ctx_pool = mempool_create_slab_pool(
num_prealloc_crypt_ctxs,
bio_crypt_ctx_cache);
if (!bio_crypt_ctx_pool)
return -ENOMEM;
return 0;
}
struct bio_crypt_ctx *bio_crypt_alloc_ctx(gfp_t gfp_mask)
{
return mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
}
EXPORT_SYMBOL(bio_crypt_alloc_ctx);
void bio_crypt_free_ctx(struct bio *bio)
{
mempool_free(bio->bi_crypt_context, bio_crypt_ctx_pool);
bio->bi_crypt_context = NULL;
}
EXPORT_SYMBOL(bio_crypt_free_ctx);
int bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
{
/*
* If a bio is swhandled, then it will be decrypted when bio_endio
* is called. As we only want the data to be decrypted once, copies
* of the bio must not have have a crypt context.
*/
if (!bio_has_crypt_ctx(src) || bio_crypt_swhandled(src))
return 0;
dst->bi_crypt_context = bio_crypt_alloc_ctx(gfp_mask);
if (!dst->bi_crypt_context)
return -ENOMEM;
*dst->bi_crypt_context = *src->bi_crypt_context;
if (bio_crypt_has_keyslot(src))
keyslot_manager_get_slot(src->bi_crypt_context->processing_ksm,
src->bi_crypt_context->keyslot);
return 0;
}
EXPORT_SYMBOL(bio_crypt_clone);
bool bio_crypt_should_process(struct bio *bio, struct request_queue *q)
{
if (!bio_has_crypt_ctx(bio))
return false;
if (q->ksm != bio->bi_crypt_context->processing_ksm)
return false;
WARN_ON(!bio_crypt_has_keyslot(bio));
return true;
}
EXPORT_SYMBOL(bio_crypt_should_process);
/*
* Checks that two bio crypt contexts are compatible - i.e. that
* they are mergeable except for data_unit_num continuity.
*/
bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2)
{
struct bio_crypt_ctx *bc1 = b_1->bi_crypt_context;
struct bio_crypt_ctx *bc2 = b_2->bi_crypt_context;
if (bio_has_crypt_ctx(b_1) != bio_has_crypt_ctx(b_2))
return false;
if (!bio_has_crypt_ctx(b_1))
return true;
return bc1->keyslot == bc2->keyslot &&
bc1->data_unit_size_bits == bc2->data_unit_size_bits;
}
/*
* Checks that two bio crypt contexts are compatible, and also
* that their data_unit_nums are continuous (and can hence be merged)
*/
bool bio_crypt_ctx_back_mergeable(struct bio *b_1,
unsigned int b1_sectors,
struct bio *b_2)
{
struct bio_crypt_ctx *bc1 = b_1->bi_crypt_context;
struct bio_crypt_ctx *bc2 = b_2->bi_crypt_context;
if (!bio_crypt_ctx_compatible(b_1, b_2))
return false;
return !bio_has_crypt_ctx(b_1) ||
(bc1->data_unit_num +
(b1_sectors >> (bc1->data_unit_size_bits - 9)) ==
bc2->data_unit_num);
}
void bio_crypt_ctx_release_keyslot(struct bio *bio)
{
struct bio_crypt_ctx *crypt_ctx = bio->bi_crypt_context;
keyslot_manager_put_slot(crypt_ctx->processing_ksm, crypt_ctx->keyslot);
bio->bi_crypt_context->processing_ksm = NULL;
bio->bi_crypt_context->keyslot = -1;
}
int bio_crypt_ctx_acquire_keyslot(struct bio *bio, struct keyslot_manager *ksm)
{
int slot;
enum blk_crypto_mode_num crypto_mode = bio_crypto_mode(bio);
if (!ksm)
return -ENOMEM;
slot = keyslot_manager_get_slot_for_key(ksm,
bio_crypt_raw_key(bio), crypto_mode,
1 << bio->bi_crypt_context->data_unit_size_bits);
if (slot < 0)
return slot;
bio_crypt_set_keyslot(bio, slot, ksm);
return 0;
}

23
block/bio.c
View file

@ -29,6 +29,7 @@
#include <linux/workqueue.h>
#include <linux/cgroup.h>
#include <linux/blk-cgroup.h>
#include <linux/blk-crypto.h>
#include <trace/events/block.h>
#include "blk.h"
@ -253,6 +254,7 @@ static void bio_free(struct bio *bio)
struct bio_set *bs = bio->bi_pool;
void *p;
bio_crypt_free_ctx(bio);
bio_uninit(bio);
if (bs) {
@ -632,15 +634,15 @@ struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
__bio_clone_fast(b, bio);
if (bio_integrity(bio)) {
int ret;
if (bio_crypt_clone(b, bio, gfp_mask) < 0) {
bio_put(b);
return NULL;
}
ret = bio_integrity_clone(b, bio, gfp_mask);
if (ret < 0) {
bio_put(b);
return NULL;
}
if (bio_integrity(bio) &&
bio_integrity_clone(b, bio, gfp_mask) < 0) {
bio_put(b);
return NULL;
}
return b;
@ -953,6 +955,7 @@ void bio_advance(struct bio *bio, unsigned bytes)
if (bio_integrity(bio))
bio_integrity_advance(bio, bytes);
bio_crypt_advance(bio, bytes);
bio_advance_iter(bio, &bio->bi_iter, bytes);
}
EXPORT_SYMBOL(bio_advance);
@ -1751,6 +1754,10 @@ void bio_endio(struct bio *bio)
again:
if (!bio_remaining_done(bio))
return;
if (!blk_crypto_endio(bio))
return;
if (!bio_integrity_endio(bio))
return;

14
block/blk-core.c
View file

@ -36,6 +36,7 @@
#include <linux/debugfs.h>
#include <linux/bpf.h>
#include <linux/psi.h>
#include <linux/blk-crypto.h>
#define CREATE_TRACE_POINTS
#include <trace/events/block.h>
@ -2462,7 +2463,9 @@ blk_qc_t generic_make_request(struct bio *bio)
/* Create a fresh bio_list for all subordinate requests */
bio_list_on_stack[1] = bio_list_on_stack[0];
bio_list_init(&bio_list_on_stack[0]);
ret = q->make_request_fn(q, bio);
if (!blk_crypto_submit_bio(&bio))
ret = q->make_request_fn(q, bio);
/* sort new bios into those for a lower level
* and those for the same level
@ -2516,6 +2519,9 @@ blk_qc_t direct_make_request(struct bio *bio)
if (!generic_make_request_checks(bio))
return BLK_QC_T_NONE;
if (blk_crypto_submit_bio(&bio))
return BLK_QC_T_NONE;
if (unlikely(blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0))) {
if (nowait && !blk_queue_dying(q))
bio->bi_status = BLK_STS_AGAIN;
@ -3992,5 +3998,11 @@ int __init blk_dev_init(void)
blk_debugfs_root = debugfs_create_dir("block", NULL);
#endif
if (bio_crypt_ctx_init() < 0)
panic("Failed to allocate mem for bio crypt ctxs\n");
if (blk_crypto_init() < 0)
panic("Failed to init blk-crypto\n");
return 0;
}

797
block/blk-crypto.c Normal file
View file

@ -0,0 +1,797 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2019 Google LLC
*/
/*
* Refer to Documentation/block/inline-encryption.rst for detailed explanation.
*/
#define pr_fmt(fmt) "blk-crypto: " fmt
#include <linux/blk-crypto.h>
#include <linux/keyslot-manager.h>
#include <linux/mempool.h>
#include <linux/blk-cgroup.h>
#include <linux/crypto.h>
#include <crypto/skcipher.h>
#include <crypto/algapi.h>
#include <linux/module.h>
#include <linux/sched/mm.h>
/* Represents a crypto mode supported by blk-crypto */
struct blk_crypto_mode {
const char *cipher_str; /* crypto API name (for fallback case) */
size_t keysize; /* key size in bytes */
};
static const struct blk_crypto_mode blk_crypto_modes[] = {
[BLK_ENCRYPTION_MODE_AES_256_XTS] = {
.cipher_str = "xts(aes)",
.keysize = 64,
},
};
static unsigned int num_prealloc_bounce_pg = 32;
module_param(num_prealloc_bounce_pg, uint, 0);
MODULE_PARM_DESC(num_prealloc_bounce_pg,
"Number of preallocated bounce pages for blk-crypto to use during crypto API fallback encryption");
#define BLK_CRYPTO_MAX_KEY_SIZE 64
static int blk_crypto_num_keyslots = 100;
module_param_named(num_keyslots, blk_crypto_num_keyslots, int, 0);
MODULE_PARM_DESC(num_keyslots,
"Number of keyslots for crypto API fallback in blk-crypto.");
static struct blk_crypto_keyslot {
struct crypto_skcipher *tfm;
enum blk_crypto_mode_num crypto_mode;
u8 key[BLK_CRYPTO_MAX_KEY_SIZE];
struct crypto_skcipher *tfms[ARRAY_SIZE(blk_crypto_modes)];
} *blk_crypto_keyslots;
/*
* Allocating a crypto tfm during I/O can deadlock, so we have to preallocate
* all of a mode's tfms when that mode starts being used. Since each mode may
* need all the keyslots at some point, each mode needs its own tfm for each
* keyslot; thus, a keyslot may contain tfms for multiple modes. However, to
* match the behavior of real inline encryption hardware (which only supports a
* single encryption context per keyslot), we only allow one tfm per keyslot to
* be used at a time - the rest of the unused tfms have their keys cleared.
*/
static struct mutex tfms_lock[ARRAY_SIZE(blk_crypto_modes)];
static bool tfms_inited[ARRAY_SIZE(blk_crypto_modes)];
struct work_mem {
struct work_struct crypto_work;
struct bio *bio;
};
/* The following few vars are only used during the crypto API fallback */
static struct keyslot_manager *blk_crypto_ksm;
static struct workqueue_struct *blk_crypto_wq;
static mempool_t *blk_crypto_page_pool;
static struct kmem_cache *blk_crypto_work_mem_cache;
bool bio_crypt_swhandled(struct bio *bio)
{
return bio_has_crypt_ctx(bio) &&
bio->bi_crypt_context->processing_ksm == blk_crypto_ksm;
}
static u8 blank_key[BLK_CRYPTO_MAX_KEY_SIZE];
static void evict_keyslot(unsigned int slot)
{
struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
enum blk_crypto_mode_num crypto_mode = slotp->crypto_mode;
int err;
WARN_ON(slotp->crypto_mode == BLK_ENCRYPTION_MODE_INVALID);
/* Clear the key in the skcipher */
err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], blank_key,
blk_crypto_modes[crypto_mode].keysize);
WARN_ON(err);
memzero_explicit(slotp->key, BLK_CRYPTO_MAX_KEY_SIZE);
slotp->crypto_mode = BLK_ENCRYPTION_MODE_INVALID;
}
static int blk_crypto_keyslot_program(void *priv, const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size,
unsigned int slot)
{
struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
const struct blk_crypto_mode *mode = &blk_crypto_modes[crypto_mode];
size_t keysize = mode->keysize;
int err;
if (crypto_mode != slotp->crypto_mode &&
slotp->crypto_mode != BLK_ENCRYPTION_MODE_INVALID) {
evict_keyslot(slot);
}
if (!slotp->tfms[crypto_mode])
return -ENOMEM;
slotp->crypto_mode = crypto_mode;
err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], key, keysize);
if (err) {
evict_keyslot(slot);
return err;
}
memcpy(slotp->key, key, keysize);
return 0;
}
static int blk_crypto_keyslot_evict(void *priv, const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size,
unsigned int slot)
{
evict_keyslot(slot);
return 0;
}
static int blk_crypto_keyslot_find(void *priv,
const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size_bytes)
{
int slot;
const size_t keysize = blk_crypto_modes[crypto_mode].keysize;
for (slot = 0; slot < blk_crypto_num_keyslots; slot++) {
if (blk_crypto_keyslots[slot].crypto_mode == crypto_mode &&
!crypto_memneq(blk_crypto_keyslots[slot].key, key, keysize))
return slot;
}
return -ENOKEY;
}
static bool blk_crypto_mode_supported(void *priv,
enum blk_crypto_mode_num crypt_mode,
unsigned int data_unit_size)
{
/* All blk_crypto_modes are required to have a crypto API fallback. */
return true;
}
/*
* The crypto API fallback KSM ops - only used for a bio when it specifies a
* blk_crypto_mode for which we failed to get a keyslot in the device's inline
* encryption hardware (which probably means the device doesn't have inline
* encryption hardware that supports that crypto mode).
*/
static const struct keyslot_mgmt_ll_ops blk_crypto_ksm_ll_ops = {
.keyslot_program = blk_crypto_keyslot_program,
.keyslot_evict = blk_crypto_keyslot_evict,
.keyslot_find = blk_crypto_keyslot_find,
.crypto_mode_supported = blk_crypto_mode_supported,
};
static void blk_crypto_encrypt_endio(struct bio *enc_bio)
{
struct bio *src_bio = enc_bio->bi_private;
int i;
for (i = 0; i < enc_bio->bi_vcnt; i++)
mempool_free(enc_bio->bi_io_vec[i].bv_page,
blk_crypto_page_pool);
src_bio->bi_status = enc_bio->bi_status;
bio_put(enc_bio);
bio_endio(src_bio);
}
static struct bio *blk_crypto_clone_bio(struct bio *bio_src)
{
struct bvec_iter iter;
struct bio_vec bv;
struct bio *bio;
bio = bio_alloc_bioset(GFP_NOIO, bio_segments(bio_src), NULL);
if (!bio)
return NULL;
bio->bi_disk = bio_src->bi_disk;
bio->bi_opf = bio_src->bi_opf;
bio->bi_ioprio = bio_src->bi_ioprio;
bio->bi_write_hint = bio_src->bi_write_hint;
bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
bio_for_each_segment(bv, bio_src, iter)
bio->bi_io_vec[bio->bi_vcnt++] = bv;
if (bio_integrity(bio_src) &&
bio_integrity_clone(bio, bio_src, GFP_NOIO) < 0) {
bio_put(bio);
return NULL;
}
bio_clone_blkcg_association(bio, bio_src);
return bio;
}
/* Check that all I/O segments are data unit aligned */
static int bio_crypt_check_alignment(struct bio *bio)
{
int data_unit_size = 1 << bio->bi_crypt_context->data_unit_size_bits;
struct bvec_iter iter;
struct bio_vec bv;
bio_for_each_segment(bv, bio, iter) {
if (!IS_ALIGNED(bv.bv_len | bv.bv_offset, data_unit_size))
return -EIO;
}
return 0;
}
static int blk_crypto_alloc_cipher_req(struct bio *src_bio,
struct skcipher_request **ciph_req_ptr,
struct crypto_wait *wait)
{
int slot;
struct skcipher_request *ciph_req;
struct blk_crypto_keyslot *slotp;
slot = bio_crypt_get_keyslot(src_bio);
slotp = &blk_crypto_keyslots[slot];
ciph_req = skcipher_request_alloc(slotp->tfms[slotp->crypto_mode],
GFP_NOIO);
if (!ciph_req) {
src_bio->bi_status = BLK_STS_RESOURCE;
return -ENOMEM;
}
skcipher_request_set_callback(ciph_req,
CRYPTO_TFM_REQ_MAY_BACKLOG |
CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, wait);
*ciph_req_ptr = ciph_req;
return 0;
}
static int blk_crypto_split_bio_if_needed(struct bio **bio_ptr)
{
struct bio *bio = *bio_ptr;
unsigned int i = 0;
unsigned int num_sectors = 0;
struct bio_vec bv;
struct bvec_iter iter;
bio_for_each_segment(bv, bio, iter) {
num_sectors += bv.bv_len >> SECTOR_SHIFT;
if (++i == BIO_MAX_PAGES)
break;
}
if (num_sectors < bio_sectors(bio)) {
struct bio *split_bio;
split_bio = bio_split(bio, num_sectors, GFP_NOIO, NULL);
if (!split_bio) {
bio->bi_status = BLK_STS_RESOURCE;
return -ENOMEM;
}
bio_chain(split_bio, bio);
generic_make_request(bio);
*bio_ptr = split_bio;
}
return 0;
}
/*
* The crypto API fallback's encryption routine.
* Allocate a bounce bio for encryption, encrypt the input bio using
* crypto API, and replace *bio_ptr with the bounce bio. May split input
* bio if it's too large.
*/
static int blk_crypto_encrypt_bio(struct bio **bio_ptr)
{
struct bio *src_bio;
struct skcipher_request *ciph_req = NULL;
DECLARE_CRYPTO_WAIT(wait);
int err = 0;
u64 curr_dun;
union {
__le64 dun;
u8 bytes[16];
} iv;
struct scatterlist src, dst;
struct bio *enc_bio;
struct bio_vec *enc_bvec;
int i, j;
int data_unit_size;
/* Split the bio if it's too big for single page bvec */
err = blk_crypto_split_bio_if_needed(bio_ptr);
if (err)
return err;
src_bio = *bio_ptr;
data_unit_size = 1 << src_bio->bi_crypt_context->data_unit_size_bits;
/* Allocate bounce bio for encryption */
enc_bio = blk_crypto_clone_bio(src_bio);
if (!enc_bio) {
src_bio->bi_status = BLK_STS_RESOURCE;
return -ENOMEM;
}
/*
* Use the crypto API fallback keyslot manager to get a crypto_skcipher
* for the algorithm and key specified for this bio.
*/
err = bio_crypt_ctx_acquire_keyslot(src_bio, blk_crypto_ksm);
if (err) {
src_bio->bi_status = BLK_STS_IOERR;
goto out_put_enc_bio;
}
/* and then allocate an skcipher_request for it */
err = blk_crypto_alloc_cipher_req(src_bio, &ciph_req, &wait);
if (err)
goto out_release_keyslot;
curr_dun = bio_crypt_data_unit_num(src_bio);
sg_init_table(&src, 1);
sg_init_table(&dst, 1);
skcipher_request_set_crypt(ciph_req, &src, &dst,
data_unit_size, iv.bytes);
/* Encrypt each page in the bounce bio */
for (i = 0, enc_bvec = enc_bio->bi_io_vec; i < enc_bio->bi_vcnt;
enc_bvec++, i++) {
struct page *plaintext_page = enc_bvec->bv_page;
struct page *ciphertext_page =
mempool_alloc(blk_crypto_page_pool, GFP_NOIO);
enc_bvec->bv_page = ciphertext_page;
if (!ciphertext_page) {
src_bio->bi_status = BLK_STS_RESOURCE;
err = -ENOMEM;
goto out_free_bounce_pages;
}
sg_set_page(&src, plaintext_page, data_unit_size,
enc_bvec->bv_offset);
sg_set_page(&dst, ciphertext_page, data_unit_size,
enc_bvec->bv_offset);
/* Encrypt each data unit in this page */
for (j = 0; j < enc_bvec->bv_len; j += data_unit_size) {
memset(&iv, 0, sizeof(iv));
iv.dun = cpu_to_le64(curr_dun);
err = crypto_wait_req(crypto_skcipher_encrypt(ciph_req),
&wait);
if (err) {
i++;
src_bio->bi_status = BLK_STS_RESOURCE;
goto out_free_bounce_pages;
}
curr_dun++;
src.offset += data_unit_size;
dst.offset += data_unit_size;
}
}
enc_bio->bi_private = src_bio;
enc_bio->bi_end_io = blk_crypto_encrypt_endio;
*bio_ptr = enc_bio;
enc_bio = NULL;
err = 0;
goto out_free_ciph_req;
out_free_bounce_pages:
while (i > 0)
mempool_free(enc_bio->bi_io_vec[--i].bv_page,
blk_crypto_page_pool);
out_free_ciph_req:
skcipher_request_free(ciph_req);
out_release_keyslot:
bio_crypt_ctx_release_keyslot(src_bio);
out_put_enc_bio:
if (enc_bio)
bio_put(enc_bio);
return err;
}
/*
* The crypto API fallback's main decryption routine.
* Decrypts input bio in place.
*/
static void blk_crypto_decrypt_bio(struct work_struct *w)
{
struct work_mem *work_mem =
container_of(w, struct work_mem, crypto_work);
struct bio *bio = work_mem->bio;
struct skcipher_request *ciph_req = NULL;
DECLARE_CRYPTO_WAIT(wait);
struct bio_vec bv;
struct bvec_iter iter;
u64 curr_dun;
union {
__le64 dun;
u8 bytes[16];
} iv;
struct scatterlist sg;
int data_unit_size = 1 << bio->bi_crypt_context->data_unit_size_bits;
int i;
int err;
/*
* Use the crypto API fallback keyslot manager to get a crypto_skcipher
* for the algorithm and key specified for this bio.
*/
if (bio_crypt_ctx_acquire_keyslot(bio, blk_crypto_ksm)) {
bio->bi_status = BLK_STS_RESOURCE;
goto out_no_keyslot;
}
/* and then allocate an skcipher_request for it */
err = blk_crypto_alloc_cipher_req(bio, &ciph_req, &wait);
if (err)
goto out;
curr_dun = bio_crypt_sw_data_unit_num(bio);
sg_init_table(&sg, 1);
skcipher_request_set_crypt(ciph_req, &sg, &sg, data_unit_size,
iv.bytes);
/* Decrypt each segment in the bio */
__bio_for_each_segment(bv, bio, iter,
bio->bi_crypt_context->crypt_iter) {
struct page *page = bv.bv_page;
sg_set_page(&sg, page, data_unit_size, bv.bv_offset);
/* Decrypt each data unit in the segment */
for (i = 0; i < bv.bv_len; i += data_unit_size) {
memset(&iv, 0, sizeof(iv));
iv.dun = cpu_to_le64(curr_dun);
if (crypto_wait_req(crypto_skcipher_decrypt(ciph_req),
&wait)) {
bio->bi_status = BLK_STS_IOERR;
goto out;
}
curr_dun++;
sg.offset += data_unit_size;
}
}
out:
skcipher_request_free(ciph_req);
bio_crypt_ctx_release_keyslot(bio);
out_no_keyslot:
kmem_cache_free(blk_crypto_work_mem_cache, work_mem);
bio_endio(bio);
}
/* Queue bio for decryption */
static void blk_crypto_queue_decrypt_bio(struct bio *bio)
{
struct work_mem *work_mem =
kmem_cache_zalloc(blk_crypto_work_mem_cache, GFP_ATOMIC);
if (!work_mem) {
bio->bi_status = BLK_STS_RESOURCE;
bio_endio(bio);
return;
}
INIT_WORK(&work_mem->crypto_work, blk_crypto_decrypt_bio);
work_mem->bio = bio;
queue_work(blk_crypto_wq, &work_mem->crypto_work);
}
/**
* blk_crypto_submit_bio - handle submitting bio for inline encryption
*
* @bio_ptr: pointer to original bio pointer
*
* If the bio doesn't have inline encryption enabled or the submitter already
* specified a keyslot for the target device, do nothing. Else, a raw key must
* have been provided, so acquire a device keyslot for it if supported. Else,
* use the crypto API fallback.
*
* When the crypto API fallback is used for encryption, blk-crypto may choose to
* split the bio into 2 - the first one that will continue to be processed and
* the second one that will be resubmitted via generic_make_request.
* A bounce bio will be allocated to encrypt the contents of the aforementioned
* "first one", and *bio_ptr will be updated to this bounce bio.
*
* Return: 0 if bio submission should continue; nonzero if bio_endio() was
* already called so bio submission should abort.
*/
int blk_crypto_submit_bio(struct bio **bio_ptr)
{
struct bio *bio = *bio_ptr;
struct request_queue *q;
int err;
struct bio_crypt_ctx *crypt_ctx;
if (!bio_has_crypt_ctx(bio) || !bio_has_data(bio))
return 0;
/*
* When a read bio is marked for sw decryption, its bi_iter is saved
* so that when we decrypt the bio later, we know what part of it was
* marked for sw decryption (when the bio is passed down after
* blk_crypto_submit bio, it may be split or advanced so we cannot rely
* on the bi_iter while decrypting in blk_crypto_endio)
*/
if (bio_crypt_swhandled(bio))
return 0;
err = bio_crypt_check_alignment(bio);
if (err) {
bio->bi_status = BLK_STS_IOERR;
goto out;
}
crypt_ctx = bio->bi_crypt_context;
q = bio->bi_disk->queue;
if (bio_crypt_has_keyslot(bio)) {
/* Key already programmed into device? */
if (q->ksm == crypt_ctx->processing_ksm)
return 0;
/* Nope, release the existing keyslot. */
bio_crypt_ctx_release_keyslot(bio);
}
/* Get device keyslot if supported */
if (q->ksm) {
err = bio_crypt_ctx_acquire_keyslot(bio, q->ksm);
if (!err)
return 0;
pr_warn_once("Failed to acquire keyslot for %s (err=%d). Falling back to crypto API.\n",
bio->bi_disk->disk_name, err);
}
/* Fallback to crypto API */
if (!READ_ONCE(tfms_inited[bio->bi_crypt_context->crypto_mode])) {
err = -EIO;
bio->bi_status = BLK_STS_IOERR;
goto out;
}
if (bio_data_dir(bio) == WRITE) {
/* Encrypt the data now */
err = blk_crypto_encrypt_bio(bio_ptr);
if (err)
goto out;
} else {
/* Mark bio as swhandled */
bio->bi_crypt_context->processing_ksm = blk_crypto_ksm;
bio->bi_crypt_context->crypt_iter = bio->bi_iter;
bio->bi_crypt_context->sw_data_unit_num =
bio->bi_crypt_context->data_unit_num;
}
return 0;
out:
bio_endio(*bio_ptr);
return err;
}
/**
* blk_crypto_endio - clean up bio w.r.t inline encryption during bio_endio
*
* @bio - the bio to clean up
*
* If blk_crypto_submit_bio decided to fallback to crypto API for this
* bio, we queue the bio for decryption into a workqueue and return false,
* and call bio_endio(bio) at a later time (after the bio has been decrypted).
*
* If the bio is not to be decrypted by the crypto API, this function releases
* the reference to the keyslot that blk_crypto_submit_bio got.
*
* Return: true if bio_endio should continue; false otherwise (bio_endio will
* be called again when bio has been decrypted).
*/
bool blk_crypto_endio(struct bio *bio)
{
if (!bio_has_crypt_ctx(bio))
return true;
if (bio_crypt_swhandled(bio)) {
/*
* The only bios that are swhandled when they reach here
* are those with bio_data_dir(bio) == READ, since WRITE
* bios that are encrypted by the crypto API fallback are
* handled by blk_crypto_encrypt_endio.
*/
/* If there was an IO error, don't decrypt. */
if (bio->bi_status)
return true;
blk_crypto_queue_decrypt_bio(bio);
return false;
}
if (bio_crypt_has_keyslot(bio))
bio_crypt_ctx_release_keyslot(bio);
return true;
}
/**
* blk_crypto_start_using_mode() - Allocate skciphers for a
* mode_num for all keyslots
* @mode_num - the blk_crypto_mode we want to allocate ciphers for.
*
* Upper layers (filesystems) should call this function to ensure that a
* the crypto API fallback has transforms for this algorithm, if they become
* necessary.
*
* Return: 0 on success and -err on error.
*/
int blk_crypto_start_using_mode(enum blk_crypto_mode_num mode_num,
unsigned int data_unit_size,
struct request_queue *q)
{
struct blk_crypto_keyslot *slotp;
int err = 0;
int i;
/*
* Fast path
* Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
* for each i are visible before we try to access them.
*/
if (likely(smp_load_acquire(&tfms_inited[mode_num])))
return 0;
/*
* If the keyslot manager of the request queue supports this
* crypto mode, then we don't need to allocate this mode.
*/
if (keyslot_manager_crypto_mode_supported(q->ksm, mode_num,
data_unit_size)) {
return 0;
}
mutex_lock(&tfms_lock[mode_num]);
if (likely(tfms_inited[mode_num]))
goto out;
for (i = 0; i < blk_crypto_num_keyslots; i++) {
slotp = &blk_crypto_keyslots[i];
slotp->tfms[mode_num] = crypto_alloc_skcipher(
blk_crypto_modes[mode_num].cipher_str,
0, 0);
if (IS_ERR(slotp->tfms[mode_num])) {
err = PTR_ERR(slotp->tfms[mode_num]);
slotp->tfms[mode_num] = NULL;
goto out_free_tfms;
}
crypto_skcipher_set_flags(slotp->tfms[mode_num],
CRYPTO_TFM_REQ_WEAK_KEY);
}
/*
* Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
* for each i are visible before we set tfms_inited[mode_num].
*/
smp_store_release(&tfms_inited[mode_num], true);
goto out;
out_free_tfms:
for (i = 0; i < blk_crypto_num_keyslots; i++) {
slotp = &blk_crypto_keyslots[i];
crypto_free_skcipher(slotp->tfms[mode_num]);
slotp->tfms[mode_num] = NULL;
}
out:
mutex_unlock(&tfms_lock[mode_num]);
return err;
}
EXPORT_SYMBOL(blk_crypto_start_using_mode);
/**
* blk_crypto_evict_key() - Evict a key from any inline encryption hardware
* it may have been programmed into
* @q - The request queue who's keyslot manager this key might have been
* programmed into
* @key - The key to evict
* @mode - The blk_crypto_mode_num used with this key
* @data_unit_size - The data unit size used with this key
*
* Upper layers (filesystems) should call this function to ensure that a key
* is evicted from hardware that it might have been programmed into. This
* will call keyslot_manager_evict_key on the queue's keyslot manager, if one
* exists, and supports the crypto algorithm with the specified data unit size.
* Otherwise, it will evict the key from the blk_crypto_ksm.
*
* Return: 0 on success, -err on error.
*/
int blk_crypto_evict_key(struct request_queue *q, const u8 *key,
enum blk_crypto_mode_num mode,
unsigned int data_unit_size)
{
struct keyslot_manager *ksm = blk_crypto_ksm;
if (q && q->ksm && keyslot_manager_crypto_mode_supported(q->ksm, mode,
data_unit_size)) {
ksm = q->ksm;
}
return keyslot_manager_evict_key(ksm, key, mode, data_unit_size);
}
EXPORT_SYMBOL(blk_crypto_evict_key);
int __init blk_crypto_init(void)
{
int i;
int err = -ENOMEM;
prandom_bytes(blank_key, BLK_CRYPTO_MAX_KEY_SIZE);
blk_crypto_ksm = keyslot_manager_create(blk_crypto_num_keyslots,
&blk_crypto_ksm_ll_ops,
NULL);
if (!blk_crypto_ksm)
goto out;
blk_crypto_wq = alloc_workqueue("blk_crypto_wq",
WQ_UNBOUND | WQ_HIGHPRI |
WQ_MEM_RECLAIM,
num_online_cpus());
if (!blk_crypto_wq)
goto out_free_ksm;
blk_crypto_keyslots = kcalloc(blk_crypto_num_keyslots,
sizeof(*blk_crypto_keyslots),
GFP_KERNEL);
if (!blk_crypto_keyslots)
goto out_free_workqueue;
for (i = 0; i < blk_crypto_num_keyslots; i++) {
blk_crypto_keyslots[i].crypto_mode =
BLK_ENCRYPTION_MODE_INVALID;
}
for (i = 0; i < ARRAY_SIZE(blk_crypto_modes); i++)
mutex_init(&tfms_lock[i]);
blk_crypto_page_pool =
mempool_create_page_pool(num_prealloc_bounce_pg, 0);
if (!blk_crypto_page_pool)
goto out_free_keyslots;
blk_crypto_work_mem_cache = KMEM_CACHE(work_mem, SLAB_RECLAIM_ACCOUNT);
if (!blk_crypto_work_mem_cache)
goto out_free_page_pool;
return 0;
out_free_page_pool:
mempool_destroy(blk_crypto_page_pool);
blk_crypto_page_pool = NULL;
out_free_keyslots:
kzfree(blk_crypto_keyslots);
blk_crypto_keyslots = NULL;
out_free_workqueue:
destroy_workqueue(blk_crypto_wq);
blk_crypto_wq = NULL;
out_free_ksm:
keyslot_manager_destroy(blk_crypto_ksm);
blk_crypto_ksm = NULL;
out:
pr_warn("No memory for blk-crypto crypto API fallback.");
return err;
}

30
block/blk-merge.c
View file

@ -495,6 +495,9 @@ static inline int ll_new_hw_segment(struct request_queue *q,
if (blk_integrity_merge_bio(q, req, bio) == false)
goto no_merge;
if (WARN_ON_ONCE(!bio_crypt_ctx_compatible(bio, req->bio)))
goto no_merge;
/*
* This will form the start of a new hw segment. Bump both
* counters.
@ -708,6 +711,11 @@ static struct request *attempt_merge(struct request_queue *q,
if (req->write_hint != next->write_hint)
return NULL;
if (!bio_crypt_ctx_back_mergeable(req->bio, blk_rq_sectors(req),
next->bio)) {
return NULL;
}
/*
* If we are allowed to merge, then append bio list
* from next to rq and release next. merge_requests_fn
@ -838,18 +846,32 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
if (rq->write_hint != bio->bi_write_hint)
return false;
/* Only merge if the crypt contexts are compatible */
if (!bio_crypt_ctx_compatible(bio, rq->bio))
return false;
return true;
}
enum elv_merge blk_try_merge(struct request *rq, struct bio *bio)
{
if (req_op(rq) == REQ_OP_DISCARD &&
queue_max_discard_segments(rq->q) > 1)
queue_max_discard_segments(rq->q) > 1) {
return ELEVATOR_DISCARD_MERGE;
else if (blk_rq_pos(rq) + blk_rq_sectors(rq) ==
bio->bi_iter.bi_sector)
} else if (blk_rq_pos(rq) + blk_rq_sectors(rq) ==
bio->bi_iter.bi_sector) {
if (!bio_crypt_ctx_back_mergeable(rq->bio,
blk_rq_sectors(rq), bio)) {
return ELEVATOR_NO_MERGE;
}
return ELEVATOR_BACK_MERGE;
else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector)
} else if (blk_rq_pos(rq) - bio_sectors(bio) ==
bio->bi_iter.bi_sector) {
if (!bio_crypt_ctx_back_mergeable(bio,
bio_sectors(bio), rq->bio)) {
return ELEVATOR_NO_MERGE;
}
return ELEVATOR_FRONT_MERGE;
}
return ELEVATOR_NO_MERGE;
}

15
block/bounce.c
View file

@ -267,14 +267,15 @@ static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask,
break;
}
if (bio_integrity(bio_src)) {
int ret;
if (bio_crypt_clone(bio, bio_src, gfp_mask) < 0) {
bio_put(bio);
return NULL;
}
ret = bio_integrity_clone(bio, bio_src, gfp_mask);
if (ret < 0) {
bio_put(bio);
return NULL;
}
if (bio_integrity(bio_src) &&
bio_integrity_clone(bio, bio_src, gfp_mask) < 0) {
bio_put(bio);
return NULL;
}
bio_clone_blkcg_association(bio, bio_src);

352
block/keyslot-manager.c Normal file
View file

@ -0,0 +1,352 @@
// SPDX-License-Identifier: GPL-2.0
/*
* keyslot-manager.c
*
* Copyright 2019 Google LLC
*/
/**
* DOC: The Keyslot Manager
*
* Many devices with inline encryption support have a limited number of "slots"
* into which encryption contexts may be programmed, and requests can be tagged
* with a slot number to specify the key to use for en/decryption.
*
* As the number of slots are limited, and programming keys is expensive on
* many inline encryption hardware, we don't want to program the same key into
* multiple slots - if multiple requests are using the same key, we want to
* program just one slot with that key and use that slot for all requests.
*
* The keyslot manager manages these keyslots appropriately, and also acts as
* an abstraction between the inline encryption hardware and the upper layers.
*
* Lower layer devices will set up a keyslot manager in their request queue
* and tell it how to perform device specific operations like programming/
* evicting keys from keyslots.
*
* Upper layers will call keyslot_manager_get_slot_for_key() to program a
* key into some slot in the inline encryption hardware.
*/
#include <linux/keyslot-manager.h>
#include <linux/atomic.h>
#include <linux/mutex.h>
#include <linux/wait.h>
#include <linux/blkdev.h>
struct keyslot {
atomic_t slot_refs;
struct list_head idle_slot_node;
};
struct keyslot_manager {
unsigned int num_slots;
atomic_t num_idle_slots;
struct keyslot_mgmt_ll_ops ksm_ll_ops;
void *ll_priv_data;
/* Protects programming and evicting keys from the device */
struct rw_semaphore lock;
/* List of idle slots, with least recently used slot at front */
wait_queue_head_t idle_slots_wait_queue;
struct list_head idle_slots;
spinlock_t idle_slots_lock;
/* Per-keyslot data */
struct keyslot slots[];
};
/**
* keyslot_manager_create() - Create a keyslot manager
* @num_slots: The number of key slots to manage.
* @ksm_ll_ops: The struct keyslot_mgmt_ll_ops for the device that this keyslot
* manager will use to perform operations like programming and
* evicting keys.
* @ll_priv_data: Private data passed as is to the functions in ksm_ll_ops.
*
* Allocate memory for and initialize a keyslot manager. Called by e.g.
* storage drivers to set up a keyslot manager in their request_queue.
*
* Context: May sleep
* Return: Pointer to constructed keyslot manager or NULL on error.
*/
struct keyslot_manager *keyslot_manager_create(unsigned int num_slots,
const struct keyslot_mgmt_ll_ops *ksm_ll_ops,
void *ll_priv_data)
{
struct keyslot_manager *ksm;
int slot;
if (num_slots == 0)
return NULL;
/* Check that all ops are specified */
if (ksm_ll_ops->keyslot_program == NULL ||
ksm_ll_ops->keyslot_evict == NULL ||
ksm_ll_ops->crypto_mode_supported == NULL ||
ksm_ll_ops->keyslot_find == NULL)
return NULL;
ksm = kvzalloc(struct_size(ksm, slots, num_slots), GFP_KERNEL);
if (!ksm)
return NULL;
ksm->num_slots = num_slots;
atomic_set(&ksm->num_idle_slots, num_slots);
ksm->ksm_ll_ops = *ksm_ll_ops;
ksm->ll_priv_data = ll_priv_data;
init_rwsem(&ksm->lock);
init_waitqueue_head(&ksm->idle_slots_wait_queue);
INIT_LIST_HEAD(&ksm->idle_slots);
for (slot = 0; slot < num_slots; slot++) {
list_add_tail(&ksm->slots[slot].idle_slot_node,
&ksm->idle_slots);
}
spin_lock_init(&ksm->idle_slots_lock);
return ksm;
}
EXPORT_SYMBOL(keyslot_manager_create);
static void remove_slot_from_lru_list(struct keyslot_manager *ksm, int slot)
{
unsigned long flags;
spin_lock_irqsave(&ksm->idle_slots_lock, flags);
list_del(&ksm->slots[slot].idle_slot_node);
spin_unlock_irqrestore(&ksm->idle_slots_lock, flags);
atomic_dec(&ksm->num_idle_slots);
}
static int find_and_grab_keyslot(struct keyslot_manager *ksm, const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size)
{
int slot;
slot = ksm->ksm_ll_ops.keyslot_find(ksm->ll_priv_data, key,
crypto_mode, data_unit_size);
if (slot < 0)
return slot;
if (WARN_ON(slot >= ksm->num_slots))
return -EINVAL;
if (atomic_inc_return(&ksm->slots[slot].slot_refs) == 1) {
/* Took first reference to this slot; remove it from LRU list */
remove_slot_from_lru_list(ksm, slot);
}
return slot;
}
/**
* keyslot_manager_get_slot_for_key() - Program a key into a keyslot.
* @ksm: The keyslot manager to program the key into.
* @key: Pointer to the bytes of the key to program. Must be the correct length
* for the chosen @crypto_mode; see blk_crypto_modes in blk-crypto.c.
* @crypto_mode: Identifier for the encryption algorithm to use.
* @data_unit_size: The data unit size to use for en/decryption.
*
* Get a keyslot that's been programmed with the specified key, crypto_mode, and
* data_unit_size. If one already exists, return it with incremented refcount.
* Otherwise, wait for a keyslot to become idle and program it.
*
* Context: Process context. Takes and releases ksm->lock.
* Return: The keyslot on success, else a -errno value.
*/
int keyslot_manager_get_slot_for_key(struct keyslot_manager *ksm,
const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size)
{
int slot;
int err;
struct keyslot *idle_slot;
down_read(&ksm->lock);
slot = find_and_grab_keyslot(ksm, key, crypto_mode, data_unit_size);
up_read(&ksm->lock);
if (slot != -ENOKEY)
return slot;
for (;;) {
down_write(&ksm->lock);
slot = find_and_grab_keyslot(ksm, key, crypto_mode,
data_unit_size);
if (slot != -ENOKEY) {
up_write(&ksm->lock);
return slot;
}
/*
* If we're here, that means there wasn't a slot that was
* already programmed with the key. So try to program it.
*/
if (atomic_read(&ksm->num_idle_slots) > 0)
break;
up_write(&ksm->lock);
wait_event(ksm->idle_slots_wait_queue,
(atomic_read(&ksm->num_idle_slots) > 0));
}
idle_slot = list_first_entry(&ksm->idle_slots, struct keyslot,
idle_slot_node);
slot = idle_slot - ksm->slots;
err = ksm->ksm_ll_ops.keyslot_program(ksm->ll_priv_data, key,
crypto_mode,
data_unit_size,
slot);
if (err) {
wake_up(&ksm->idle_slots_wait_queue);
up_write(&ksm->lock);
return err;
}
atomic_set(&ksm->slots[slot].slot_refs, 1);
remove_slot_from_lru_list(ksm, slot);
up_write(&ksm->lock);
return slot;
}
EXPORT_SYMBOL(keyslot_manager_get_slot_for_key);
/**
* keyslot_manager_get_slot() - Increment the refcount on the specified slot.
* @ksm - The keyslot manager that we want to modify.
* @slot - The slot to increment the refcount of.
*
* This function assumes that there is already an active reference to that slot
* and simply increments the refcount. This is useful when cloning a bio that
* already has a reference to a keyslot, and we want the cloned bio to also have
* its own reference.
*
* Context: Any context.
*/
void keyslot_manager_get_slot(struct keyslot_manager *ksm, unsigned int slot)
{
if (WARN_ON(slot >= ksm->num_slots))
return;
WARN_ON(atomic_inc_return(&ksm->slots[slot].slot_refs) < 2);
}
EXPORT_SYMBOL(keyslot_manager_get_slot);
/**
* keyslot_manager_put_slot() - Release a reference to a slot
* @ksm: The keyslot manager to release the reference from.
* @slot: The slot to release the reference from.
*
* Context: Any context.
*/
void keyslot_manager_put_slot(struct keyslot_manager *ksm, unsigned int slot)
{
unsigned long flags;
if (WARN_ON(slot >= ksm->num_slots))
return;
if (atomic_dec_and_lock_irqsave(&ksm->slots[slot].slot_refs,
&ksm->idle_slots_lock, flags)) {
list_add_tail(&ksm->slots[slot].idle_slot_node,
&ksm->idle_slots);
spin_unlock_irqrestore(&ksm->idle_slots_lock, flags);
atomic_inc(&ksm->num_idle_slots);
wake_up(&ksm->idle_slots_wait_queue);
}
}
EXPORT_SYMBOL(keyslot_manager_put_slot);
/**
* keyslot_manager_crypto_mode_supported() - Find out if a crypto_mode/data
* unit size combination is supported
* by a ksm.
* @ksm - The keyslot manager to check
* @crypto_mode - The crypto mode to check for.
* @data_unit_size - The data_unit_size for the mode.
*
* Calls and returns the result of the crypto_mode_supported function specified
* by the ksm.
*
* Context: Process context.
* Return: Whether or not this ksm supports the specified crypto_mode/
* data_unit_size combo.
*/
bool keyslot_manager_crypto_mode_supported(struct keyslot_manager *ksm,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size)
{
if (!ksm)
return false;
return ksm->ksm_ll_ops.crypto_mode_supported(ksm->ll_priv_data,
crypto_mode,
data_unit_size);
}
EXPORT_SYMBOL(keyslot_manager_crypto_mode_supported);
bool keyslot_manager_rq_crypto_mode_supported(struct request_queue *q,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size)
{
return keyslot_manager_crypto_mode_supported(q->ksm, crypto_mode,
data_unit_size);
}
EXPORT_SYMBOL(keyslot_manager_rq_crypto_mode_supported);
/**
* keyslot_manager_evict_key() - Evict a key from the lower layer device.
* @ksm - The keyslot manager to evict from
* @key - The key to evict
* @crypto_mode - The crypto algorithm the key was programmed with.
* @data_unit_size - The data_unit_size the key was programmed with.
*
* Finds the slot that the specified key, crypto_mode, data_unit_size combo
* was programmed into, and evicts that slot from the lower layer device if
* the refcount on the slot is 0. Returns -EBUSY if the refcount is not 0, and
* -errno on error.
*
* Context: Process context. Takes and releases ksm->lock.
*/
int keyslot_manager_evict_key(struct keyslot_manager *ksm,
const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size)
{
int slot;
int err = 0;
down_write(&ksm->lock);
slot = ksm->ksm_ll_ops.keyslot_find(ksm->ll_priv_data, key,
crypto_mode,
data_unit_size);
if (slot < 0) {
up_write(&ksm->lock);
return slot;
}
if (atomic_read(&ksm->slots[slot].slot_refs) == 0) {
err = ksm->ksm_ll_ops.keyslot_evict(ksm->ll_priv_data, key,
crypto_mode,
data_unit_size,
slot);
} else {
err = -EBUSY;
}
up_write(&ksm->lock);
return err;
}
EXPORT_SYMBOL(keyslot_manager_evict_key);
void keyslot_manager_destroy(struct keyslot_manager *ksm)
{
kvfree(ksm);
}
EXPORT_SYMBOL(keyslot_manager_destroy);

15
drivers/md/dm.c
View file

@ -1312,12 +1312,15 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio,
sector_t sector, unsigned len)
{
struct bio *clone = &tio->clone;
int ret;
__bio_clone_fast(clone, bio);
if (unlikely(bio_integrity(bio) != NULL)) {
int r;
ret = bio_crypt_clone(clone, bio, GFP_NOIO);
if (ret < 0)
return ret;
if (unlikely(bio_integrity(bio) != NULL)) {
if (unlikely(!dm_target_has_integrity(tio->ti->type) &&
!dm_target_passes_integrity(tio->ti->type))) {
DMWARN("%s: the target %s doesn't support integrity data.",
@ -1326,9 +1329,11 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio,
return -EIO;
}
r = bio_integrity_clone(clone, bio, GFP_NOIO);
if (r < 0)
return r;
ret = bio_integrity_clone(clone, bio, GFP_NOIO);
if (ret < 0) {
bio_crypt_free_ctx(clone);
return ret;
}
}
if (bio_op(bio) != REQ_OP_ZONE_REPORT)

9
drivers/scsi/ufs/Kconfig
View file

@ -131,3 +131,12 @@ config SCSI_UFS_HISI
Select this if you have UFS controller on Hisilicon chipset.
If unsure, say N.
config SCSI_UFS_CRYPTO
bool "UFS Crypto Engine Support"
depends on SCSI_UFSHCD && BLK_INLINE_ENCRYPTION
help
Enable Crypto Engine Support in UFS.
Enabling this makes it possible for the kernel to use the crypto
capabilities of the UFS device (if present) to perform crypto
operations on data being transferred to/from the device.

1
drivers/scsi/ufs/Makefile
View file

@ -11,3 +11,4 @@ obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
obj-$(CONFIG_SCSI_UFS_TEST) += ufs_test.o
obj-$(CONFIG_DEBUG_FS) += ufs-debugfs.o ufs-qcom-debugfs.o
obj-$(CONFIG_SCSI_UFS_HISI) += ufs-hisi.o
ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o

8
drivers/scsi/ufs/ufs-hisi.c
View file

@ -540,6 +540,14 @@ static int ufs_hisi_init_common(struct ufs_hba *hba)
if (!host)
return -ENOMEM;
/*
* Inline crypto is currently broken with ufs-hisi because the keyslots
* overlap with the vendor-specific SYS CTRL registers -- and even if
* software uses only non-overlapping keyslots, the kernel crashes when
* programming a key or a UFS error occurs on the first encrypted I/O.
*/
hba->quirks |= UFSHCD_QUIRK_BROKEN_CRYPTO;
host->hba = hba;
ufshcd_set_variant(hba, host);

6
drivers/scsi/ufs/ufs-qcom.c
View file

@ -1459,6 +1459,12 @@ static void ufs_qcom_advertise_quirks(struct ufs_hba *hba)
if (host->disable_lpm)
hba->quirks |= UFSHCD_QUIRK_BROKEN_AUTO_HIBERN8;
/*
* Inline crypto is currently broken with ufs-qcom at least because the
* device tree doesn't include the crypto registers. There are likely
* to be other issues that will need to be addressed too.
*/
//hba->quirks |= UFSHCD_QUIRK_BROKEN_CRYPTO;
}
static void ufs_qcom_set_caps(struct ufs_hba *hba)

521
drivers/scsi/ufs/ufshcd-crypto.c Normal file
View file

@ -0,0 +1,521 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2019 Google LLC
*/
#include <crypto/algapi.h>
#include "ufshcd.h"
#include "ufshcd-crypto.h"
static bool ufshcd_cap_idx_valid(struct ufs_hba *hba, unsigned int cap_idx)
{
return cap_idx < hba->crypto_capabilities.num_crypto_cap;
}
static u8 get_data_unit_size_mask(unsigned int data_unit_size)
{
if (data_unit_size < 512 || data_unit_size > 65536 ||
!is_power_of_2(data_unit_size))
return 0;
return data_unit_size / 512;
}
static size_t get_keysize_bytes(enum ufs_crypto_key_size size)
{
switch (size) {
case UFS_CRYPTO_KEY_SIZE_128: return 16;
case UFS_CRYPTO_KEY_SIZE_192: return 24;
case UFS_CRYPTO_KEY_SIZE_256: return 32;
case UFS_CRYPTO_KEY_SIZE_512: return 64;
default: return 0;
}
}
static int ufshcd_crypto_cap_find(void *hba_p,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size)
{
struct ufs_hba *hba = hba_p;
enum ufs_crypto_alg ufs_alg;
u8 data_unit_mask;
int cap_idx;
enum ufs_crypto_key_size ufs_key_size;
union ufs_crypto_cap_entry *ccap_array = hba->crypto_cap_array;
if (!ufshcd_hba_is_crypto_supported(hba))
return -EINVAL;
switch (crypto_mode) {
case BLK_ENCRYPTION_MODE_AES_256_XTS:
ufs_alg = UFS_CRYPTO_ALG_AES_XTS;
ufs_key_size = UFS_CRYPTO_KEY_SIZE_256;
break;
default: return -EINVAL;
}
data_unit_mask = get_data_unit_size_mask(data_unit_size);
for (cap_idx = 0; cap_idx < hba->crypto_capabilities.num_crypto_cap;
cap_idx++) {
if (ccap_array[cap_idx].algorithm_id == ufs_alg &&
(ccap_array[cap_idx].sdus_mask & data_unit_mask) &&
ccap_array[cap_idx].key_size == ufs_key_size)
return cap_idx;
}
return -EINVAL;
}
/**
* ufshcd_crypto_cfg_entry_write_key - Write a key into a crypto_cfg_entry
*
* Writes the key with the appropriate format - for AES_XTS,
* the first half of the key is copied as is, the second half is
* copied with an offset halfway into the cfg->crypto_key array.
* For the other supported crypto algs, the key is just copied.
*
* @cfg: The crypto config to write to
* @key: The key to write
* @cap: The crypto capability (which specifies the crypto alg and key size)
*
* Returns 0 on success, or -EINVAL
*/
static int ufshcd_crypto_cfg_entry_write_key(union ufs_crypto_cfg_entry *cfg,
const u8 *key,
union ufs_crypto_cap_entry cap)
{
size_t key_size_bytes = get_keysize_bytes(cap.key_size);
if (key_size_bytes == 0)
return -EINVAL;
switch (cap.algorithm_id) {
case UFS_CRYPTO_ALG_AES_XTS:
key_size_bytes *= 2;
if (key_size_bytes > UFS_CRYPTO_KEY_MAX_SIZE)
return -EINVAL;
memcpy(cfg->crypto_key, key, key_size_bytes/2);
memcpy(cfg->crypto_key + UFS_CRYPTO_KEY_MAX_SIZE/2,
key + key_size_bytes/2, key_size_bytes/2);
return 0;
case UFS_CRYPTO_ALG_BITLOCKER_AES_CBC: // fallthrough
case UFS_CRYPTO_ALG_AES_ECB: // fallthrough
case UFS_CRYPTO_ALG_ESSIV_AES_CBC:
memcpy(cfg->crypto_key, key, key_size_bytes);
return 0;
}
return -EINVAL;
}
static void program_key(struct ufs_hba *hba,
const union ufs_crypto_cfg_entry *cfg,
int slot)
{
int i;
u32 slot_offset = hba->crypto_cfg_register + slot * sizeof(*cfg);
/* Clear the dword 16 */
ufshcd_writel(hba, 0, slot_offset + 16 * sizeof(cfg->reg_val[0]));
/* Ensure that CFGE is cleared before programming the key */
wmb();
for (i = 0; i < 16; i++) {
ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[i]),
slot_offset + i * sizeof(cfg->reg_val[0]));
/* Spec says each dword in key must be written sequentially */
wmb();
}
/* Write dword 17 */
ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[17]),
slot_offset + 17 * sizeof(cfg->reg_val[0]));
/* Dword 16 must be written last */
wmb();
/* Write dword 16 */
ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[16]),
slot_offset + 16 * sizeof(cfg->reg_val[0]));
wmb();
}
static int ufshcd_crypto_keyslot_program(void *hba_p, const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size,
unsigned int slot)
{
struct ufs_hba *hba = hba_p;
int err = 0;
u8 data_unit_mask;
union ufs_crypto_cfg_entry cfg;
union ufs_crypto_cfg_entry *cfg_arr = hba->crypto_cfgs;
int cap_idx;
cap_idx = ufshcd_crypto_cap_find(hba_p, crypto_mode,
data_unit_size);
if (!ufshcd_is_crypto_enabled(hba) ||
!ufshcd_keyslot_valid(hba, slot) ||
!ufshcd_cap_idx_valid(hba, cap_idx))
return -EINVAL;
data_unit_mask = get_data_unit_size_mask(data_unit_size);
if (!(data_unit_mask & hba->crypto_cap_array[cap_idx].sdus_mask))
return -EINVAL;
memset(&cfg, 0, sizeof(cfg));
cfg.data_unit_size = data_unit_mask;
cfg.crypto_cap_idx = cap_idx;
cfg.config_enable |= UFS_CRYPTO_CONFIGURATION_ENABLE;
err = ufshcd_crypto_cfg_entry_write_key(&cfg, key,
hba->crypto_cap_array[cap_idx]);
if (err)
return err;
program_key(hba, &cfg, slot);
memcpy(&cfg_arr[slot], &cfg, sizeof(cfg));
memzero_explicit(&cfg, sizeof(cfg));
return 0;
}
static int ufshcd_crypto_keyslot_find(void *hba_p,
const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size)
{
struct ufs_hba *hba = hba_p;
int err = 0;
int slot;
u8 data_unit_mask;
union ufs_crypto_cfg_entry cfg;
union ufs_crypto_cfg_entry *cfg_arr = hba->crypto_cfgs;
int cap_idx;
cap_idx = ufshcd_crypto_cap_find(hba_p, crypto_mode,
data_unit_size);
if (!ufshcd_is_crypto_enabled(hba) ||
!ufshcd_cap_idx_valid(hba, cap_idx))
return -EINVAL;
data_unit_mask = get_data_unit_size_mask(data_unit_size);
if (!(data_unit_mask & hba->crypto_cap_array[cap_idx].sdus_mask))
return -EINVAL;
memset(&cfg, 0, sizeof(cfg));
err = ufshcd_crypto_cfg_entry_write_key(&cfg, key,
hba->crypto_cap_array[cap_idx]);
if (err)
return -EINVAL;
for (slot = 0; slot < NUM_KEYSLOTS(hba); slot++) {
if ((cfg_arr[slot].config_enable &
UFS_CRYPTO_CONFIGURATION_ENABLE) &&
data_unit_mask == cfg_arr[slot].data_unit_size &&
cap_idx == cfg_arr[slot].crypto_cap_idx &&
!crypto_memneq(&cfg.crypto_key, cfg_arr[slot].crypto_key,
UFS_CRYPTO_KEY_MAX_SIZE)) {
memzero_explicit(&cfg, sizeof(cfg));
return slot;
}
}
memzero_explicit(&cfg, sizeof(cfg));
return -ENOKEY;
}
static int ufshcd_crypto_keyslot_evict(void *hba_p, const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size,
unsigned int slot)
{
struct ufs_hba *hba = hba_p;
int i = 0;
u32 reg_base;
union ufs_crypto_cfg_entry *cfg_arr = hba->crypto_cfgs;
if (!ufshcd_is_crypto_enabled(hba) ||
!ufshcd_keyslot_valid(hba, slot))
return -EINVAL;
memset(&cfg_arr[slot], 0, sizeof(cfg_arr[slot]));
reg_base = hba->crypto_cfg_register + slot * sizeof(cfg_arr[0]);
/*
* Clear the crypto cfg on the device. Clearing CFGE
* might not be sufficient, so just clear the entire cfg.
*/
for (i = 0; i < sizeof(cfg_arr[0]); i += sizeof(__le32))
ufshcd_writel(hba, 0, reg_base + i);
wmb();
return 0;
}
static bool ufshcd_crypto_mode_supported(void *hba_p,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size)
{
return ufshcd_crypto_cap_find(hba_p, crypto_mode, data_unit_size) >= 0;
}
/* Functions implementing UFSHCI v2.1 specification behaviour */
void ufshcd_crypto_enable_spec(struct ufs_hba *hba)
{
union ufs_crypto_cfg_entry *cfg_arr = hba->crypto_cfgs;
int slot;
if (!ufshcd_hba_is_crypto_supported(hba))
return;
hba->caps |= UFSHCD_CAP_CRYPTO;
/*
* Reset might clear all keys, so reprogram all the keys.
* Also serves to clear keys on driver init.
*/
for (slot = 0; slot < NUM_KEYSLOTS(hba); slot++)
program_key(hba, &cfg_arr[slot], slot);
}
EXPORT_SYMBOL(ufshcd_crypto_enable_spec);
void ufshcd_crypto_disable_spec(struct ufs_hba *hba)
{
hba->caps &= ~UFSHCD_CAP_CRYPTO;
}
EXPORT_SYMBOL(ufshcd_crypto_disable_spec);
static const struct keyslot_mgmt_ll_ops ufshcd_ksm_ops = {
.keyslot_program = ufshcd_crypto_keyslot_program,
.keyslot_evict = ufshcd_crypto_keyslot_evict,
.keyslot_find = ufshcd_crypto_keyslot_find,
.crypto_mode_supported = ufshcd_crypto_mode_supported,
};
/**
* ufshcd_hba_init_crypto - Read crypto capabilities, init crypto fields in hba
* @hba: Per adapter instance
*
* Return: 0 if crypto was initialized or is not supported, else a -errno value.
*/
int ufshcd_hba_init_crypto_spec(struct ufs_hba *hba,
const struct keyslot_mgmt_ll_ops *ksm_ops)
{
int cap_idx = 0;
int err = 0;
/* Default to disabling crypto */
hba->caps &= ~UFSHCD_CAP_CRYPTO;
/* Return 0 if crypto support isn't present */
if (!(hba->capabilities & MASK_CRYPTO_SUPPORT) ||
(hba->quirks & UFSHCD_QUIRK_BROKEN_CRYPTO))
goto out;
/*
* Crypto Capabilities should never be 0, because the
* config_array_ptr > 04h. So we use a 0 value to indicate that
* crypto init failed, and can't be enabled.
*/
hba->crypto_capabilities.reg_val =
cpu_to_le32(ufshcd_readl(hba, REG_UFS_CCAP));
hba->crypto_cfg_register =
(u32)hba->crypto_capabilities.config_array_ptr * 0x100;
hba->crypto_cap_array =
devm_kcalloc(hba->dev,
hba->crypto_capabilities.num_crypto_cap,
sizeof(hba->crypto_cap_array[0]),
GFP_KERNEL);
if (!hba->crypto_cap_array) {
err = -ENOMEM;
goto out;
}
hba->crypto_cfgs =
devm_kcalloc(hba->dev,
NUM_KEYSLOTS(hba),
sizeof(hba->crypto_cfgs[0]),
GFP_KERNEL);
if (!hba->crypto_cfgs) {
err = -ENOMEM;
goto out_free_cfg_mem;
}
/*
* Store all the capabilities now so that we don't need to repeatedly
* access the device each time we want to know its capabilities
*/
for (cap_idx = 0; cap_idx < hba->crypto_capabilities.num_crypto_cap;
cap_idx++) {
hba->crypto_cap_array[cap_idx].reg_val =
cpu_to_le32(ufshcd_readl(hba,
REG_UFS_CRYPTOCAP +
cap_idx * sizeof(__le32)));
}
hba->ksm = keyslot_manager_create(NUM_KEYSLOTS(hba), ksm_ops, hba);
if (!hba->ksm) {
err = -ENOMEM;
goto out_free_crypto_cfgs;
}
return 0;
out_free_crypto_cfgs:
devm_kfree(hba->dev, hba->crypto_cfgs);
out_free_cfg_mem:
devm_kfree(hba->dev, hba->crypto_cap_array);
out:
/* Indicate that init failed by setting crypto_capabilities to 0 */
hba->crypto_capabilities.reg_val = 0;
return err;
}
EXPORT_SYMBOL(ufshcd_hba_init_crypto_spec);
void ufshcd_crypto_setup_rq_keyslot_manager_spec(struct ufs_hba *hba,
struct request_queue *q)
{
if (!ufshcd_hba_is_crypto_supported(hba) || !q)
return;
q->ksm = hba->ksm;
}
EXPORT_SYMBOL(ufshcd_crypto_setup_rq_keyslot_manager_spec);
void ufshcd_crypto_destroy_rq_keyslot_manager_spec(struct ufs_hba *hba,
struct request_queue *q)
{
keyslot_manager_destroy(hba->ksm);
}
EXPORT_SYMBOL(ufshcd_crypto_destroy_rq_keyslot_manager_spec);
int ufshcd_prepare_lrbp_crypto_spec(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp)
{
int key_slot;
if (!cmd->request->bio ||
!bio_crypt_should_process(cmd->request->bio, cmd->request->q)) {
lrbp->crypto_enable = false;
return 0;
}
if (WARN_ON(!ufshcd_is_crypto_enabled(hba))) {
/*
* Upper layer asked us to do inline encryption
* but that isn't enabled, so we fail this request.
*/
return -EINVAL;
}
key_slot = bio_crypt_get_keyslot(cmd->request->bio);
if (!ufshcd_keyslot_valid(hba, key_slot))
return -EINVAL;
lrbp->crypto_enable = true;
lrbp->crypto_key_slot = key_slot;
lrbp->data_unit_num = bio_crypt_data_unit_num(cmd->request->bio);
return 0;
}
EXPORT_SYMBOL(ufshcd_prepare_lrbp_crypto_spec);
/* Crypto Variant Ops Support */
void ufshcd_crypto_enable(struct ufs_hba *hba)
{
if (hba->crypto_vops && hba->crypto_vops->enable)
return hba->crypto_vops->enable(hba);
return ufshcd_crypto_enable_spec(hba);
}
void ufshcd_crypto_disable(struct ufs_hba *hba)
{
if (hba->crypto_vops && hba->crypto_vops->disable)
return hba->crypto_vops->disable(hba);
return ufshcd_crypto_disable_spec(hba);
}
int ufshcd_hba_init_crypto(struct ufs_hba *hba)
{
if (hba->crypto_vops && hba->crypto_vops->hba_init_crypto)
return hba->crypto_vops->hba_init_crypto(hba,
&ufshcd_ksm_ops);
return ufshcd_hba_init_crypto_spec(hba, &ufshcd_ksm_ops);
}
void ufshcd_crypto_setup_rq_keyslot_manager(struct ufs_hba *hba,
struct request_queue *q)
{
if (hba->crypto_vops && hba->crypto_vops->setup_rq_keyslot_manager)
return hba->crypto_vops->setup_rq_keyslot_manager(hba, q);
return ufshcd_crypto_setup_rq_keyslot_manager_spec(hba, q);
}
void ufshcd_crypto_destroy_rq_keyslot_manager(struct ufs_hba *hba,
struct request_queue *q)
{
if (hba->crypto_vops && hba->crypto_vops->destroy_rq_keyslot_manager)
return hba->crypto_vops->destroy_rq_keyslot_manager(hba, q);
return ufshcd_crypto_destroy_rq_keyslot_manager_spec(hba, q);
}
int ufshcd_prepare_lrbp_crypto(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp)
{
if (hba->crypto_vops && hba->crypto_vops->prepare_lrbp_crypto)
return hba->crypto_vops->prepare_lrbp_crypto(hba, cmd, lrbp);
return ufshcd_prepare_lrbp_crypto_spec(hba, cmd, lrbp);
}
int ufshcd_complete_lrbp_crypto(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp)
{
if (hba->crypto_vops && hba->crypto_vops->complete_lrbp_crypto)
return hba->crypto_vops->complete_lrbp_crypto(hba, cmd, lrbp);
return 0;
}
void ufshcd_crypto_debug(struct ufs_hba *hba)
{
if (hba->crypto_vops && hba->crypto_vops->debug)
hba->crypto_vops->debug(hba);
}
int ufshcd_crypto_suspend(struct ufs_hba *hba,
enum ufs_pm_op pm_op)
{
if (hba->crypto_vops && hba->crypto_vops->suspend)
return hba->crypto_vops->suspend(hba, pm_op);
return 0;
}
int ufshcd_crypto_resume(struct ufs_hba *hba,
enum ufs_pm_op pm_op)
{
if (hba->crypto_vops && hba->crypto_vops->resume)
return hba->crypto_vops->resume(hba, pm_op);
return 0;
}
void ufshcd_crypto_set_vops(struct ufs_hba *hba,
struct ufs_hba_crypto_variant_ops *crypto_vops)
{
hba->crypto_vops = crypto_vops;
}

151
drivers/scsi/ufs/ufshcd-crypto.h Normal file
View file

@ -0,0 +1,151 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright 2019 Google LLC
*/
#ifndef _UFSHCD_CRYPTO_H
#define _UFSHCD_CRYPTO_H
#ifdef CONFIG_SCSI_UFS_CRYPTO
#include <linux/keyslot-manager.h>
#include "ufshcd.h"
#include "ufshci.h"
#define NUM_KEYSLOTS(hba) (hba->crypto_capabilities.config_count + 1)
static inline bool ufshcd_keyslot_valid(struct ufs_hba *hba, unsigned int slot)
{
/*
* The actual number of configurations supported is (CFGC+1), so slot
* numbers range from 0 to config_count inclusive.
*/
return slot < NUM_KEYSLOTS(hba);
}
static inline bool ufshcd_hba_is_crypto_supported(struct ufs_hba *hba)
{
return hba->crypto_capabilities.reg_val != 0;
}
static inline bool ufshcd_is_crypto_enabled(struct ufs_hba *hba)
{
return hba->caps & UFSHCD_CAP_CRYPTO;
}
/* Functions implementing UFSHCI v2.1 specification behaviour */
int ufshcd_prepare_lrbp_crypto_spec(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp);
void ufshcd_crypto_enable_spec(struct ufs_hba *hba);
void ufshcd_crypto_disable_spec(struct ufs_hba *hba);
struct keyslot_mgmt_ll_ops;
int ufshcd_hba_init_crypto_spec(struct ufs_hba *hba,
const struct keyslot_mgmt_ll_ops *ksm_ops);
void ufshcd_crypto_setup_rq_keyslot_manager_spec(struct ufs_hba *hba,
struct request_queue *q);
void ufshcd_crypto_destroy_rq_keyslot_manager_spec(struct ufs_hba *hba,
struct request_queue *q);
/* Crypto Variant Ops Support */
void ufshcd_crypto_enable(struct ufs_hba *hba);
void ufshcd_crypto_disable(struct ufs_hba *hba);
int ufshcd_hba_init_crypto(struct ufs_hba *hba);
void ufshcd_crypto_setup_rq_keyslot_manager(struct ufs_hba *hba,
struct request_queue *q);
void ufshcd_crypto_destroy_rq_keyslot_manager(struct ufs_hba *hba,
struct request_queue *q);
int ufshcd_prepare_lrbp_crypto(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp);
int ufshcd_complete_lrbp_crypto(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp);
void ufshcd_crypto_debug(struct ufs_hba *hba);
int ufshcd_crypto_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op);
int ufshcd_crypto_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op);
void ufshcd_crypto_set_vops(struct ufs_hba *hba,
struct ufs_hba_crypto_variant_ops *crypto_vops);
#else /* CONFIG_SCSI_UFS_CRYPTO */
static inline bool ufshcd_keyslot_valid(struct ufs_hba *hba,
unsigned int slot)
{
return false;
}
static inline bool ufshcd_hba_is_crypto_supported(struct ufs_hba *hba)
{
return false;
}
static inline bool ufshcd_is_crypto_enabled(struct ufs_hba *hba)
{
return false;
}
static inline void ufshcd_crypto_enable(struct ufs_hba *hba) { }
static inline void ufshcd_crypto_disable(struct ufs_hba *hba) { }
static inline int ufshcd_hba_init_crypto(struct ufs_hba *hba)
{
return 0;
}
static inline void ufshcd_crypto_setup_rq_keyslot_manager(struct ufs_hba *hba,
struct request_queue *q) { }
static inline void ufshcd_crypto_destroy_rq_keyslot_manager(struct ufs_hba *hba,
struct request_queue *q) { }
static inline int ufshcd_prepare_lrbp_crypto(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp)
{
lrbp->crypto_enable = false;
return 0;
}
static inline int ufshcd_complete_lrbp_crypto(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp)
{
return 0;
}
static inline void ufshcd_crypto_debug(struct ufs_hba *hba) { }
static inline int ufshcd_crypto_suspend(struct ufs_hba *hba,
enum ufs_pm_op pm_op)
{
return 0;
}
static inline int ufshcd_crypto_resume(struct ufs_hba *hba,
enum ufs_pm_op pm_op)
{
return 0;
}
static inline void ufshcd_crypto_set_vops(struct ufs_hba *hba,
struct ufs_hba_crypto_variant_ops *crypto_vops) { }
#endif /* CONFIG_SCSI_UFS_CRYPTO */
#endif /* _UFSHCD_CRYPTO_H */

63
drivers/scsi/ufs/ufshcd.c
View file

@ -204,6 +204,7 @@ static void ufshcd_update_uic_error_cnt(struct ufs_hba *hba, u32 reg, int type)
break;
}
}
#include "ufshcd-crypto.h"
#define CREATE_TRACE_POINTS
#include <trace/events/ufs.h>
@ -905,6 +906,8 @@ static inline void __ufshcd_print_host_regs(struct ufs_hba *hba, bool no_sleep)
static void ufshcd_print_host_regs(struct ufs_hba *hba)
{
__ufshcd_print_host_regs(hba, false);
ufshcd_crypto_debug(hba);
}
static
@ -1412,8 +1415,11 @@ static inline void ufshcd_hba_start(struct ufs_hba *hba)
{
u32 val = CONTROLLER_ENABLE;
if (ufshcd_is_crypto_supported(hba))
if (ufshcd_hba_is_crypto_supported(hba)) {
ufshcd_crypto_enable(hba);
val |= CRYPTO_GENERAL_ENABLE;
}
ufshcd_writel(hba, val, REG_CONTROLLER_ENABLE);
}
@ -3399,9 +3405,21 @@ static int ufshcd_prepare_req_desc_hdr(struct ufs_hba *hba,
dword_0 |= UTP_REQ_DESC_INT_CMD;
/* Transfer request descriptor header fields */
if (lrbp->crypto_enable) {
dword_0 |= UTP_REQ_DESC_CRYPTO_ENABLE_CMD;
dword_0 |= lrbp->crypto_key_slot;
req_desc->header.dword_1 =
cpu_to_le32((u32)lrbp->data_unit_num);
req_desc->header.dword_3 =
cpu_to_le32((u32)(lrbp->data_unit_num >> 32));
} else {
/* dword_1 and dword_3 are reserved, hence they are set to 0 */
req_desc->header.dword_1 = 0;
req_desc->header.dword_3 = 0;
}
req_desc->header.dword_0 = cpu_to_le32(dword_0);
/* dword_1 is reserved, hence it is set to 0 */
req_desc->header.dword_1 = 0;
/*
* assigning invalid value for command status. Controller
* updates OCS on command completion, with the command
@ -3409,8 +3427,6 @@ static int ufshcd_prepare_req_desc_hdr(struct ufs_hba *hba,
*/
req_desc->header.dword_2 =
cpu_to_le32(OCS_INVALID_COMMAND_STATUS);
/* dword_3 is reserved, hence it is set to 0 */
req_desc->header.dword_3 = 0;
req_desc->prd_table_length = 0;
@ -3769,6 +3785,13 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
lrbp->task_tag = tag;
lrbp->lun = ufshcd_scsi_to_upiu_lun(cmd->device->lun);
lrbp->intr_cmd = !ufshcd_is_intr_aggr_allowed(hba) ? true : false;
err = ufshcd_prepare_lrbp_crypto(hba, cmd, lrbp);
if (err) {
lrbp->cmd = NULL;
clear_bit_unlock(tag, &hba->lrb_in_use);
goto out;
}
lrbp->req_abort_skip = false;
err = ufshcd_comp_scsi_upiu(hba, lrbp);
@ -3833,6 +3856,7 @@ static int ufshcd_compose_dev_cmd(struct ufs_hba *hba,
lrbp->task_tag = tag;
lrbp->lun = 0; /* device management cmd is not specific to any LUN */
lrbp->intr_cmd = true; /* No interrupt aggregation */
lrbp->crypto_enable = false; /* No crypto operations */
hba->dev_cmd.type = cmd_type;
return ufshcd_comp_devman_upiu(hba, lrbp);
@ -5734,6 +5758,8 @@ static inline void ufshcd_hba_stop(struct ufs_hba *hba, bool can_sleep)
{
int err;
ufshcd_crypto_disable(hba);
ufshcd_writel(hba, CONTROLLER_DISABLE, REG_CONTROLLER_ENABLE);
err = ufshcd_wait_for_register(hba, REG_CONTROLLER_ENABLE,
CONTROLLER_ENABLE, CONTROLLER_DISABLE,
@ -6170,6 +6196,8 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
sdev->autosuspend_delay = UFSHCD_AUTO_SUSPEND_DELAY_MS;
sdev->use_rpm_auto = 1;
ufshcd_crypto_setup_rq_keyslot_manager(hba, q);
return 0;
}
@ -6180,6 +6208,7 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
static void ufshcd_slave_destroy(struct scsi_device *sdev)
{
struct ufs_hba *hba;
struct request_queue *q = sdev->request_queue;
hba = shost_priv(sdev->host);
/* Drop the reference as it won't be needed anymore */
@ -6190,6 +6219,8 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev)
hba->sdev_ufs_device = NULL;
spin_unlock_irqrestore(hba->host->host_lock, flags);
}
ufshcd_crypto_destroy_rq_keyslot_manager(hba, q);
}
/**
@ -6463,6 +6494,7 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba,
cmd->result = result;
lrbp->compl_time_stamp = ktime_get();
update_req_stats(hba, lrbp);
ufshcd_complete_lrbp_crypto(hba, cmd, lrbp);
/* Mark completed command as NULL in LRB */
lrbp->cmd = NULL;
hba->ufs_stats.clk_rel.ctx = XFR_REQ_COMPL;
@ -10284,6 +10316,10 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
req_link_state = UIC_LINK_OFF_STATE;
}
ret = ufshcd_crypto_suspend(hba, pm_op);
if (ret)
goto out;
/*
* If we can't transition into any of the low power modes
* just gate the clocks.
@ -10412,6 +10448,7 @@ enable_gating:
hba->hibern8_on_idle.is_suspended = false;
hba->clk_gating.is_suspended = false;
ufshcd_release_all(hba);
ufshcd_crypto_resume(hba, pm_op);
out:
hba->pm_op_in_progress = 0;
@ -10435,9 +10472,11 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
{
int ret;
enum uic_link_state old_link_state;
enum ufs_dev_pwr_mode old_pwr_mode;
hba->pm_op_in_progress = 1;
old_link_state = hba->uic_link_state;
old_pwr_mode = hba->curr_dev_pwr_mode;
ufshcd_hba_vreg_set_hpm(hba);
/* Make sure clocks are enabled before accessing controller */
@ -10505,6 +10544,11 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
goto set_old_link_state;
}
}
ret = ufshcd_crypto_resume(hba, pm_op);
if (ret)
goto set_old_dev_pwr_mode;
if (ufshcd_keep_autobkops_enabled_except_suspend(hba))
ufshcd_enable_auto_bkops(hba);
else
@ -10527,6 +10571,9 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
ufshcd_release_all(hba);
goto out;
set_old_dev_pwr_mode:
if (old_pwr_mode != hba->curr_dev_pwr_mode)
ufshcd_set_dev_pwr_mode(hba, old_pwr_mode);
set_old_link_state:
ufshcd_link_state_transition(hba, old_link_state, 0);
if (ufshcd_is_link_hibern8(hba) &&
@ -11043,6 +11090,12 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
if (hba->force_g4)
hba->phy_init_g4 = true;
/* Init crypto */
err = ufshcd_hba_init_crypto(hba);
if (err) {
dev_err(hba->dev, "crypto setup failed\n");
goto out_remove_scsi_host;
}
/* Host controller enable */
err = ufshcd_hba_enable(hba);

53
drivers/scsi/ufs/ufshcd.h
View file

@ -197,6 +197,9 @@ struct ufs_pm_lvl_states {
* @intr_cmd: Interrupt command (doesn't participate in interrupt aggregation)
* @issue_time_stamp: time stamp for debug purposes
* @compl_time_stamp: time stamp for statistics
* @crypto_enable: whether or not the request needs inline crypto operations
* @crypto_key_slot: the key slot to use for inline crypto
* @data_unit_num: the data unit number for the first block for inline crypto
* @req_abort_skip: skip request abort task flag
*/
struct ufshcd_lrb {
@ -221,6 +224,9 @@ struct ufshcd_lrb {
bool intr_cmd;
ktime_t issue_time_stamp;
ktime_t compl_time_stamp;
bool crypto_enable;
u8 crypto_key_slot;
u64 data_unit_num;
bool req_abort_skip;
};
@ -390,6 +396,28 @@ struct ufs_hba_variant {
struct ufs_hba_pm_qos_variant_ops *pm_qos_vops;
};
struct keyslot_mgmt_ll_ops;
struct ufs_hba_crypto_variant_ops {
void (*setup_rq_keyslot_manager)(struct ufs_hba *hba,
struct request_queue *q);
void (*destroy_rq_keyslot_manager)(struct ufs_hba *hba,
struct request_queue *q);
int (*hba_init_crypto)(struct ufs_hba *hba,
const struct keyslot_mgmt_ll_ops *ksm_ops);
void (*enable)(struct ufs_hba *hba);
void (*disable)(struct ufs_hba *hba);
int (*suspend)(struct ufs_hba *hba, enum ufs_pm_op pm_op);
int (*resume)(struct ufs_hba *hba, enum ufs_pm_op pm_op);
int (*debug)(struct ufs_hba *hba);
int (*prepare_lrbp_crypto)(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp);
int (*complete_lrbp_crypto)(struct ufs_hba *hba,
struct scsi_cmnd *cmd,
struct ufshcd_lrb *lrbp);
void *priv;
};
/* clock gating state */
enum clk_gating_state {
CLKS_OFF,
@ -758,6 +786,11 @@ struct ufshcd_cmd_log {
* @is_urgent_bkops_lvl_checked: keeps track if the urgent bkops level for
* device is known or not.
* @scsi_block_reqs_cnt: reference counting for scsi block requests
* @crypto_capabilities: Content of crypto capabilities register (0x100)
* @crypto_cap_array: Array of crypto capabilities
* @crypto_cfg_register: Start of the crypto cfg array
* @crypto_cfgs: Array of crypto configurations (i.e. config for each slot)
* @ksm: the keyslot manager tied to this hba
*/
struct ufs_hba {
void __iomem *mmio_base;
@ -805,6 +838,7 @@ struct ufs_hba {
u32 ufs_version;
struct ufs_hba_variant *var;
void *priv;
const struct ufs_hba_crypto_variant_ops *crypto_vops;
unsigned int irq;
bool is_irq_enabled;
bool crash_on_err;
@ -909,6 +943,11 @@ struct ufs_hba {
#define UFSHCD_QUIRK_DME_PEER_GET_FAST_MODE 0x20000
#define UFSHCD_QUIRK_BROKEN_AUTO_HIBERN8 0x40000
/*
* This quirk needs to be enabled if the host controller advertises
* inline encryption support but it doesn't work correctly.
*/
#define UFSHCD_QUIRK_BROKEN_CRYPTO 0x800
unsigned int quirks; /* Deviations from standard UFSHCI spec. */
@ -1022,6 +1061,11 @@ struct ufs_hba {
* in hibern8 then enable this cap.
*/
#define UFSHCD_CAP_POWER_COLLAPSE_DURING_HIBERN8 (1 << 7)
/*
* This capability allows the host controller driver to use the
* inline crypto engine, if it is present
*/
#define UFSHCD_CAP_CRYPTO (1 << 7)
struct devfreq *devfreq;
struct ufs_clk_scaling clk_scaling;
@ -1049,6 +1093,15 @@ struct ufs_hba {
bool phy_init_g4;
bool force_g4;
bool wb_enabled;
#ifdef CONFIG_SCSI_UFS_CRYPTO
/* crypto */
union ufs_crypto_capabilities crypto_capabilities;
union ufs_crypto_cap_entry *crypto_cap_array;
u32 crypto_cfg_register;
union ufs_crypto_cfg_entry *crypto_cfgs;
struct keyslot_manager *ksm;
#endif /* CONFIG_SCSI_UFS_CRYPTO */
};
static inline void ufshcd_mark_shutdown_ongoing(struct ufs_hba *hba)

56
drivers/scsi/ufs/ufshci.h
View file

@ -363,6 +363,61 @@ enum {
INTERRUPT_MASK_ALL_VER_21 = 0x71FFF,
};
/* CCAP - Crypto Capability 100h */
union ufs_crypto_capabilities {
__le32 reg_val;
struct {
u8 num_crypto_cap;
u8 config_count;
u8 reserved;
u8 config_array_ptr;
};
};
enum ufs_crypto_key_size {
UFS_CRYPTO_KEY_SIZE_INVALID = 0x0,
UFS_CRYPTO_KEY_SIZE_128 = 0x1,
UFS_CRYPTO_KEY_SIZE_192 = 0x2,
UFS_CRYPTO_KEY_SIZE_256 = 0x3,
UFS_CRYPTO_KEY_SIZE_512 = 0x4,
};
enum ufs_crypto_alg {
UFS_CRYPTO_ALG_AES_XTS = 0x0,
UFS_CRYPTO_ALG_BITLOCKER_AES_CBC = 0x1,
UFS_CRYPTO_ALG_AES_ECB = 0x2,
UFS_CRYPTO_ALG_ESSIV_AES_CBC = 0x3,
};
/* x-CRYPTOCAP - Crypto Capability X */
union ufs_crypto_cap_entry {
__le32 reg_val;
struct {
u8 algorithm_id;
u8 sdus_mask; /* Supported data unit size mask */
u8 key_size;
u8 reserved;
};
};
#define UFS_CRYPTO_CONFIGURATION_ENABLE (1 << 7)
#define UFS_CRYPTO_KEY_MAX_SIZE 64
/* x-CRYPTOCFG - Crypto Configuration X */
union ufs_crypto_cfg_entry {
__le32 reg_val[32];
struct {
u8 crypto_key[UFS_CRYPTO_KEY_MAX_SIZE];
u8 data_unit_size;
u8 crypto_cap_idx;
u8 reserved_1;
u8 config_enable;
u8 reserved_multi_host;
u8 reserved_2;
u8 vsb[2];
u8 reserved_3[56];
};
};
/*
* Request Descriptor Definitions
*/
@ -384,6 +439,7 @@ enum {
UTP_NATIVE_UFS_COMMAND = 0x10000000,
UTP_DEVICE_MANAGEMENT_FUNCTION = 0x20000000,
UTP_REQ_DESC_INT_CMD = 0x01000000,
UTP_REQ_DESC_CRYPTO_ENABLE_CMD = 0x00800000,
};
/* UTP Transfer Request Data Direction (DD) */

3
fs/buffer.c
View file

@ -46,6 +46,7 @@
#include <linux/pagevec.h>
#include <linux/sched/mm.h>
#include <trace/events/block.h>
#include <linux/fscrypt.h>
static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
@ -3104,6 +3105,8 @@ static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
*/
bio = bio_alloc(GFP_NOIO, 1);
fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO | __GFP_NOFAIL);
if (wbc) {
wbc_init_bio(wbc, bio);
wbc_account_io(wbc, bh->b_page, bh->b_size);

8
fs/crypto/Kconfig
View file

@ -6,6 +6,8 @@ config FS_ENCRYPTION
select CRYPTO_ECB
select CRYPTO_XTS
select CRYPTO_CTS
select CRYPTO_SHA512
select CRYPTO_HMAC
select KEYS
help
Enable encryption of files and directories. This
@ -13,3 +15,9 @@ config FS_ENCRYPTION
efficient since it avoids caching the encrypted and
decrypted pages in the page cache. Currently Ext4,
F2FS and UBIFS make use of this feature.
config FS_ENCRYPTION_INLINE_CRYPT
bool "Enable fscrypt to use inline crypto"
depends on FS_ENCRYPTION && BLK_INLINE_ENCRYPTION
help
Enable fscrypt to use inline encryption hardware if available.

11
fs/crypto/Makefile
View file

@ -1,4 +1,13 @@
obj-$(CONFIG_FS_ENCRYPTION) += fscrypto.o
fscrypto-y := crypto.o fname.o hooks.o keyinfo.o policy.o
fscrypto-y := crypto.o \
fname.o \
hkdf.o \
hooks.o \
keyring.o \
keysetup.o \
keysetup_v1.o \
policy.o
fscrypto-$(CONFIG_BLOCK) += bio.o
fscrypto-$(CONFIG_FS_ENCRYPTION_INLINE_CRYPT) += inline_crypt.o

60
fs/crypto/bio.c
View file

@ -26,7 +26,7 @@
#include <linux/namei.h>
#include "fscrypt_private.h"
static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
void fscrypt_decrypt_bio(struct bio *bio)
{
struct bio_vec *bv;
int i;
@ -38,62 +38,47 @@ static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
bv->bv_offset);
if (ret)
SetPageError(page);
else if (done)
SetPageUptodate(page);
if (done)
unlock_page(page);
}
}
void fscrypt_decrypt_bio(struct bio *bio)
{
__fscrypt_decrypt_bio(bio, false);
}
EXPORT_SYMBOL(fscrypt_decrypt_bio);
static void completion_pages(struct work_struct *work)
{
struct fscrypt_ctx *ctx = container_of(work, struct fscrypt_ctx, work);
struct bio *bio = ctx->bio;
__fscrypt_decrypt_bio(bio, true);
fscrypt_release_ctx(ctx);
bio_put(bio);
}
void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, struct bio *bio)
{
INIT_WORK(&ctx->work, completion_pages);
ctx->bio = bio;
fscrypt_enqueue_decrypt_work(&ctx->work);
}
EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio);
int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
sector_t pblk, unsigned int len)
{
const unsigned int blockbits = inode->i_blkbits;
const unsigned int blocksize = 1 << blockbits;
const bool inlinecrypt = fscrypt_inode_uses_inline_crypto(inode);
struct page *ciphertext_page;
struct bio *bio;
int ret, err = 0;
ciphertext_page = fscrypt_alloc_bounce_page(GFP_NOWAIT);
if (!ciphertext_page)
return -ENOMEM;
if (inlinecrypt) {
ciphertext_page = ZERO_PAGE(0);
} else {
ciphertext_page = fscrypt_alloc_bounce_page(GFP_NOWAIT);
if (!ciphertext_page)
return -ENOMEM;
}
while (len--) {
err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk,
ZERO_PAGE(0), ciphertext_page,
blocksize, 0, GFP_NOFS);
if (err)
goto errout;
if (!inlinecrypt) {
err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk,
ZERO_PAGE(0), ciphertext_page,
blocksize, 0, GFP_NOFS);
if (err)
goto errout;
}
bio = bio_alloc(GFP_NOWAIT, 1);
if (!bio) {
err = -ENOMEM;
goto errout;
}
err = fscrypt_set_bio_crypt_ctx(bio, inode, lblk, GFP_NOIO);
if (err) {
bio_put(bio);
goto errout;
}
bio_set_dev(bio, inode->i_sb->s_bdev);
bio->bi_iter.bi_sector = pblk << (blockbits - 9);
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
@ -115,7 +100,8 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
}
err = 0;
errout:
fscrypt_free_bounce_page(ciphertext_page);
if (!inlinecrypt)
fscrypt_free_bounce_page(ciphertext_page);
return err;
}
EXPORT_SYMBOL(fscrypt_zeroout_range);

167
fs/crypto/crypto.c
View file

@ -26,29 +26,20 @@
#include <linux/ratelimit.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <crypto/aes.h>
#include <crypto/skcipher.h>
#include "fscrypt_private.h"
static unsigned int num_prealloc_crypto_pages = 32;
static unsigned int num_prealloc_crypto_ctxs = 128;
module_param(num_prealloc_crypto_pages, uint, 0444);
MODULE_PARM_DESC(num_prealloc_crypto_pages,
"Number of crypto pages to preallocate");
module_param(num_prealloc_crypto_ctxs, uint, 0444);
MODULE_PARM_DESC(num_prealloc_crypto_ctxs,
"Number of crypto contexts to preallocate");
static mempool_t *fscrypt_bounce_page_pool = NULL;
static LIST_HEAD(fscrypt_free_ctxs);
static DEFINE_SPINLOCK(fscrypt_ctx_lock);
static struct workqueue_struct *fscrypt_read_workqueue;
static DEFINE_MUTEX(fscrypt_init_mutex);
static struct kmem_cache *fscrypt_ctx_cachep;
struct kmem_cache *fscrypt_info_cachep;
void fscrypt_enqueue_decrypt_work(struct work_struct *work)
@ -57,62 +48,6 @@ void fscrypt_enqueue_decrypt_work(struct work_struct *work)
}
EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work);
/**
* fscrypt_release_ctx() - Release a decryption context
* @ctx: The decryption context to release.
*
* If the decryption context was allocated from the pre-allocated pool, return
* it to that pool. Else, free it.
*/
void fscrypt_release_ctx(struct fscrypt_ctx *ctx)
{
unsigned long flags;
if (ctx->flags & FS_CTX_REQUIRES_FREE_ENCRYPT_FL) {
kmem_cache_free(fscrypt_ctx_cachep, ctx);
} else {
spin_lock_irqsave(&fscrypt_ctx_lock, flags);
list_add(&ctx->free_list, &fscrypt_free_ctxs);
spin_unlock_irqrestore(&fscrypt_ctx_lock, flags);
}
}
EXPORT_SYMBOL(fscrypt_release_ctx);
/**
* fscrypt_get_ctx() - Get a decryption context
* @gfp_flags: The gfp flag for memory allocation
*
* Allocate and initialize a decryption context.
*
* Return: A new decryption context on success; an ERR_PTR() otherwise.
*/
struct fscrypt_ctx *fscrypt_get_ctx(gfp_t gfp_flags)
{
struct fscrypt_ctx *ctx;
unsigned long flags;
/*
* First try getting a ctx from the free list so that we don't have to
* call into the slab allocator.
*/
spin_lock_irqsave(&fscrypt_ctx_lock, flags);
ctx = list_first_entry_or_null(&fscrypt_free_ctxs,
struct fscrypt_ctx, free_list);
if (ctx)
list_del(&ctx->free_list);
spin_unlock_irqrestore(&fscrypt_ctx_lock, flags);
if (!ctx) {
ctx = kmem_cache_zalloc(fscrypt_ctx_cachep, gfp_flags);
if (!ctx)
return ERR_PTR(-ENOMEM);
ctx->flags |= FS_CTX_REQUIRES_FREE_ENCRYPT_FL;
} else {
ctx->flags &= ~FS_CTX_REQUIRES_FREE_ENCRYPT_FL;
}
return ctx;
}
EXPORT_SYMBOL(fscrypt_get_ctx);
struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags)
{
return mempool_alloc(fscrypt_bounce_page_pool, gfp_flags);
@ -137,14 +72,17 @@ EXPORT_SYMBOL(fscrypt_free_bounce_page);
void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
const struct fscrypt_info *ci)
{
u8 flags = fscrypt_policy_flags(&ci->ci_policy);
memset(iv, 0, ci->ci_mode->ivsize);
iv->lblk_num = cpu_to_le64(lblk_num);
if (ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY)
if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) {
WARN_ON_ONCE((u32)lblk_num != lblk_num);
lblk_num |= (u64)ci->ci_inode->i_ino << 32;
} else if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {
memcpy(iv->nonce, ci->ci_nonce, FS_KEY_DERIVATION_NONCE_SIZE);
if (ci->ci_essiv_tfm != NULL)
crypto_cipher_encrypt_one(ci->ci_essiv_tfm, iv->raw, iv->raw);
}
iv->lblk_num = cpu_to_le64(lblk_num);
}
/* Encrypt or decrypt a single filesystem block of file contents */
@ -187,10 +125,8 @@ int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw,
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
skcipher_request_free(req);
if (res) {
fscrypt_err(inode->i_sb,
"%scryption failed for inode %lu, block %llu: %d",
(rw == FS_DECRYPT ? "de" : "en"),
inode->i_ino, lblk_num, res);
fscrypt_err(inode, "%scryption failed for block %llu: %d",
(rw == FS_DECRYPT ? "De" : "En"), lblk_num, res);
return res;
}
return 0;
@ -397,17 +333,6 @@ const struct dentry_operations fscrypt_d_ops = {
.d_revalidate = fscrypt_d_revalidate,
};
static void fscrypt_destroy(void)
{
struct fscrypt_ctx *pos, *n;
list_for_each_entry_safe(pos, n, &fscrypt_free_ctxs, free_list)
kmem_cache_free(fscrypt_ctx_cachep, pos);
INIT_LIST_HEAD(&fscrypt_free_ctxs);
mempool_destroy(fscrypt_bounce_page_pool);
fscrypt_bounce_page_pool = NULL;
}
/**
* fscrypt_initialize() - allocate major buffers for fs encryption.
* @cop_flags: fscrypt operations flags
@ -415,11 +340,11 @@ static void fscrypt_destroy(void)
* We only call this when we start accessing encrypted files, since it
* results in memory getting allocated that wouldn't otherwise be used.
*
* Return: Zero on success, non-zero otherwise.
* Return: 0 on success; -errno on failure
*/
int fscrypt_initialize(unsigned int cop_flags)
{
int i, res = -ENOMEM;
int err = 0;
/* No need to allocate a bounce page pool if this FS won't use it. */
if (cop_flags & FS_CFLG_OWN_PAGES)
@ -427,32 +352,21 @@ int fscrypt_initialize(unsigned int cop_flags)
mutex_lock(&fscrypt_init_mutex);
if (fscrypt_bounce_page_pool)
goto already_initialized;
for (i = 0; i < num_prealloc_crypto_ctxs; i++) {
struct fscrypt_ctx *ctx;
ctx = kmem_cache_zalloc(fscrypt_ctx_cachep, GFP_NOFS);
if (!ctx)
goto fail;
list_add(&ctx->free_list, &fscrypt_free_ctxs);
}
goto out_unlock;
err = -ENOMEM;
fscrypt_bounce_page_pool =
mempool_create_page_pool(num_prealloc_crypto_pages, 0);
if (!fscrypt_bounce_page_pool)
goto fail;
goto out_unlock;
already_initialized:
err = 0;
out_unlock:
mutex_unlock(&fscrypt_init_mutex);
return 0;
fail:
fscrypt_destroy();
mutex_unlock(&fscrypt_init_mutex);
return res;
return err;
}
void fscrypt_msg(struct super_block *sb, const char *level,
void fscrypt_msg(const struct inode *inode, const char *level,
const char *fmt, ...)
{
static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
@ -466,8 +380,9 @@ void fscrypt_msg(struct super_block *sb, const char *level,
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
if (sb)
printk("%sfscrypt (%s): %pV\n", level, sb->s_id, &vaf);
if (inode)
printk("%sfscrypt (%s, inode %lu): %pV\n",
level, inode->i_sb->s_id, inode->i_ino, &vaf);
else
printk("%sfscrypt: %pV\n", level, &vaf);
va_end(args);
@ -478,6 +393,8 @@ void fscrypt_msg(struct super_block *sb, const char *level,
*/
static int __init fscrypt_init(void)
{
int err = -ENOMEM;
/*
* Use an unbound workqueue to allow bios to be decrypted in parallel
* even when they happen to complete on the same CPU. This sacrifices
@ -492,39 +409,21 @@ static int __init fscrypt_init(void)
if (!fscrypt_read_workqueue)
goto fail;
fscrypt_ctx_cachep = KMEM_CACHE(fscrypt_ctx, SLAB_RECLAIM_ACCOUNT);
if (!fscrypt_ctx_cachep)
goto fail_free_queue;
fscrypt_info_cachep = KMEM_CACHE(fscrypt_info, SLAB_RECLAIM_ACCOUNT);
if (!fscrypt_info_cachep)
goto fail_free_ctx;
goto fail_free_queue;
err = fscrypt_init_keyring();
if (err)
goto fail_free_info;
return 0;
fail_free_ctx:
kmem_cache_destroy(fscrypt_ctx_cachep);
fail_free_info:
kmem_cache_destroy(fscrypt_info_cachep);
fail_free_queue:
destroy_workqueue(fscrypt_read_workqueue);
fail:
return -ENOMEM;
return err;
}
module_init(fscrypt_init)
/**
* fscrypt_exit() - Shutdown the fs encryption system
*/
static void __exit fscrypt_exit(void)
{
fscrypt_destroy();
if (fscrypt_read_workqueue)
destroy_workqueue(fscrypt_read_workqueue);
kmem_cache_destroy(fscrypt_ctx_cachep);
kmem_cache_destroy(fscrypt_info_cachep);
fscrypt_essiv_cleanup();
}
module_exit(fscrypt_exit);
MODULE_LICENSE("GPL");
late_initcall(fscrypt_init)

47
fs/crypto/fname.c
View file

@ -71,9 +71,7 @@ int fname_encrypt(struct inode *inode, const struct qstr *iname,
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
skcipher_request_free(req);
if (res < 0) {
fscrypt_err(inode->i_sb,
"Filename encryption failed for inode %lu: %d",
inode->i_ino, res);
fscrypt_err(inode, "Filename encryption failed: %d", res);
return res;
}
@ -117,9 +115,7 @@ static int fname_decrypt(struct inode *inode,
res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait);
skcipher_request_free(req);
if (res < 0) {
fscrypt_err(inode->i_sb,
"Filename decryption failed for inode %lu: %d",
inode->i_ino, res);
fscrypt_err(inode, "Filename decryption failed: %d", res);
return res;
}
@ -127,44 +123,45 @@ static int fname_decrypt(struct inode *inode,
return 0;
}
static const char *lookup_table =
static const char lookup_table[65] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
#define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)
/**
* digest_encode() -
* base64_encode() -
*
* Encodes the input digest using characters from the set [a-zA-Z0-9_+].
* Encodes the input string using characters from the set [A-Za-z0-9+,].
* The encoded string is roughly 4/3 times the size of the input string.
*
* Return: length of the encoded string
*/
static int digest_encode(const char *src, int len, char *dst)
static int base64_encode(const u8 *src, int len, char *dst)
{
int i = 0, bits = 0, ac = 0;
int i, bits = 0, ac = 0;
char *cp = dst;
while (i < len) {
ac += (((unsigned char) src[i]) << bits);
for (i = 0; i < len; i++) {
ac += src[i] << bits;
bits += 8;
do {
*cp++ = lookup_table[ac & 0x3f];
ac >>= 6;
bits -= 6;
} while (bits >= 6);
i++;
}
if (bits)
*cp++ = lookup_table[ac & 0x3f];
return cp - dst;
}
static int digest_decode(const char *src, int len, char *dst)
static int base64_decode(const char *src, int len, u8 *dst)
{
int i = 0, bits = 0, ac = 0;
int i, bits = 0, ac = 0;
const char *p;
char *cp = dst;
u8 *cp = dst;
while (i < len) {
for (i = 0; i < len; i++) {
p = strchr(lookup_table, src[i]);
if (p == NULL || src[i] == 0)
return -2;
@ -175,7 +172,6 @@ static int digest_decode(const char *src, int len, char *dst)
ac >>= 8;
bits -= 8;
}
i++;
}
if (ac)
return -1;
@ -185,8 +181,9 @@ static int digest_decode(const char *src, int len, char *dst)
bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
u32 max_len, u32 *encrypted_len_ret)
{
int padding = 4 << (inode->i_crypt_info->ci_flags &
FS_POLICY_FLAGS_PAD_MASK);
const struct fscrypt_info *ci = inode->i_crypt_info;
int padding = 4 << (fscrypt_policy_flags(&ci->ci_policy) &
FSCRYPT_POLICY_FLAGS_PAD_MASK);
u32 encrypted_len;
if (orig_len > max_len)
@ -272,7 +269,7 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
return fname_decrypt(inode, iname, oname);
if (iname->len <= FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE) {
oname->len = digest_encode(iname->name, iname->len,
oname->len = base64_encode(iname->name, iname->len,
oname->name);
return 0;
}
@ -287,7 +284,7 @@ int fscrypt_fname_disk_to_usr(struct inode *inode,
FSCRYPT_FNAME_DIGEST(iname->name, iname->len),
FSCRYPT_FNAME_DIGEST_SIZE);
oname->name[0] = '_';
oname->len = 1 + digest_encode((const char *)&digested_name,
oname->len = 1 + base64_encode((const u8 *)&digested_name,
sizeof(digested_name), oname->name + 1);
return 0;
}
@ -380,8 +377,8 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
if (fname->crypto_buf.name == NULL)
return -ENOMEM;
ret = digest_decode(iname->name + digested, iname->len - digested,
fname->crypto_buf.name);
ret = base64_decode(iname->name + digested, iname->len - digested,
fname->crypto_buf.name);
if (ret < 0) {
ret = -ENOENT;
goto errout;

488
fs/crypto/fscrypt_private.h
View file

@ -4,9 +4,8 @@
*
* Copyright (C) 2015, Google, Inc.
*
* This contains encryption key functions.
*
* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
* Originally written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar.
* Heavily modified since then.
*/
#ifndef _FSCRYPT_PRIVATE_H
@ -14,31 +13,137 @@
#include <linux/fscrypt.h>
#include <crypto/hash.h>
#include <linux/bio-crypt-ctx.h>
struct fscrypt_master_key;
#define CONST_STRLEN(str) (sizeof(str) - 1)
/* Encryption parameters */
#define FS_KEY_DERIVATION_NONCE_SIZE 16
/**
* Encryption context for inode
*
* Protector format:
* 1 byte: Protector format (1 = this version)
* 1 byte: File contents encryption mode
* 1 byte: File names encryption mode
* 1 byte: Flags
* 8 bytes: Master Key descriptor
* 16 bytes: Encryption Key derivation nonce
*/
struct fscrypt_context {
u8 format;
#define FSCRYPT_MIN_KEY_SIZE 16
#define FSCRYPT_CONTEXT_V1 1
#define FSCRYPT_CONTEXT_V2 2
struct fscrypt_context_v1 {
u8 version; /* FSCRYPT_CONTEXT_V1 */
u8 contents_encryption_mode;
u8 filenames_encryption_mode;
u8 flags;
u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
} __packed;
};
#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
struct fscrypt_context_v2 {
u8 version; /* FSCRYPT_CONTEXT_V2 */
u8 contents_encryption_mode;
u8 filenames_encryption_mode;
u8 flags;
u8 __reserved[4];
u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
};
/**
* fscrypt_context - the encryption context of an inode
*
* This is the on-disk equivalent of an fscrypt_policy, stored alongside each
* encrypted file usually in a hidden extended attribute. It contains the
* fields from the fscrypt_policy, in order to identify the encryption algorithm
* and key with which the file is encrypted. It also contains a nonce that was
* randomly generated by fscrypt itself; this is used as KDF input or as a tweak
* to cause different files to be encrypted differently.
*/
union fscrypt_context {
u8 version;
struct fscrypt_context_v1 v1;
struct fscrypt_context_v2 v2;
};
/*
* Return the size expected for the given fscrypt_context based on its version
* number, or 0 if the context version is unrecognized.
*/
static inline int fscrypt_context_size(const union fscrypt_context *ctx)
{
switch (ctx->version) {
case FSCRYPT_CONTEXT_V1:
BUILD_BUG_ON(sizeof(ctx->v1) != 28);
return sizeof(ctx->v1);
case FSCRYPT_CONTEXT_V2:
BUILD_BUG_ON(sizeof(ctx->v2) != 40);
return sizeof(ctx->v2);
}
return 0;
}
#undef fscrypt_policy
union fscrypt_policy {
u8 version;
struct fscrypt_policy_v1 v1;
struct fscrypt_policy_v2 v2;
};
/*
* Return the size expected for the given fscrypt_policy based on its version
* number, or 0 if the policy version is unrecognized.
*/
static inline int fscrypt_policy_size(const union fscrypt_policy *policy)
{
switch (policy->version) {
case FSCRYPT_POLICY_V1:
return sizeof(policy->v1);
case FSCRYPT_POLICY_V2:
return sizeof(policy->v2);
}
return 0;
}
/* Return the contents encryption mode of a valid encryption policy */
static inline u8
fscrypt_policy_contents_mode(const union fscrypt_policy *policy)
{
switch (policy->version) {
case FSCRYPT_POLICY_V1:
return policy->v1.contents_encryption_mode;
case FSCRYPT_POLICY_V2:
return policy->v2.contents_encryption_mode;
}
BUG();
}
/* Return the filenames encryption mode of a valid encryption policy */
static inline u8
fscrypt_policy_fnames_mode(const union fscrypt_policy *policy)
{
switch (policy->version) {
case FSCRYPT_POLICY_V1:
return policy->v1.filenames_encryption_mode;
case FSCRYPT_POLICY_V2:
return policy->v2.filenames_encryption_mode;
}
BUG();
}
/* Return the flags (FSCRYPT_POLICY_FLAG*) of a valid encryption policy */
static inline u8
fscrypt_policy_flags(const union fscrypt_policy *policy)
{
switch (policy->version) {
case FSCRYPT_POLICY_V1:
return policy->v1.flags;
case FSCRYPT_POLICY_V2:
return policy->v2.flags;
}
BUG();
}
static inline bool
fscrypt_is_direct_key_policy(const union fscrypt_policy *policy)
{
return fscrypt_policy_flags(policy) & FSCRYPT_POLICY_FLAG_DIRECT_KEY;
}
/**
* For encrypted symlinks, the ciphertext length is stored at the beginning
@ -61,30 +166,49 @@ struct fscrypt_info {
/* The actual crypto transform used for encryption and decryption */
struct crypto_skcipher *ci_ctfm;
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
/*
* Cipher for ESSIV IV generation. Only set for CBC contents
* encryption, otherwise is NULL.
* The raw key for inline encryption, if this file is using inline
* encryption rather than the traditional filesystem layer encryption.
*/
struct crypto_cipher *ci_essiv_tfm;
const u8 *ci_inline_crypt_key;
#endif
/* True if the key should be freed when this fscrypt_info is freed */
bool ci_owns_key;
/*
* Encryption mode used for this inode. It corresponds to either
* ci_data_mode or ci_filename_mode, depending on the inode type.
* Encryption mode used for this inode. It corresponds to either the
* contents or filenames encryption mode, depending on the inode type.
*/
struct fscrypt_mode *ci_mode;
/*
* If non-NULL, then this inode uses a master key directly rather than a
* derived key, and ci_ctfm will equal ci_master_key->mk_ctfm.
* Otherwise, this inode uses a derived key.
*/
struct fscrypt_master_key *ci_master_key;
/* Back-pointer to the inode */
struct inode *ci_inode;
/* fields from the fscrypt_context */
u8 ci_data_mode;
u8 ci_filename_mode;
u8 ci_flags;
u8 ci_master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
/*
* The master key with which this inode was unlocked (decrypted). This
* will be NULL if the master key was found in a process-subscribed
* keyring rather than in the filesystem-level keyring.
*/
struct key *ci_master_key;
/*
* Link in list of inodes that were unlocked with the master key.
* Only used when ->ci_master_key is set.
*/
struct list_head ci_master_key_link;
/*
* If non-NULL, then encryption is done using the master key directly
* and ci_ctfm will equal ci_direct_key->dk_ctfm.
*/
struct fscrypt_direct_key *ci_direct_key;
/* The encryption policy used by this inode */
union fscrypt_policy ci_policy;
/* This inode's nonce, copied from the fscrypt_context */
u8 ci_nonce[FS_KEY_DERIVATION_NONCE_SIZE];
};
@ -93,21 +217,19 @@ typedef enum {
FS_ENCRYPT,
} fscrypt_direction_t;
#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
u32 filenames_mode)
{
if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
if (contents_mode == FSCRYPT_MODE_AES_128_CBC &&
filenames_mode == FSCRYPT_MODE_AES_128_CTS)
return true;
if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
if (contents_mode == FSCRYPT_MODE_AES_256_XTS &&
filenames_mode == FSCRYPT_MODE_AES_256_CTS)
return true;
if (contents_mode == FS_ENCRYPTION_MODE_ADIANTUM &&
filenames_mode == FS_ENCRYPTION_MODE_ADIANTUM)
if (contents_mode == FSCRYPT_MODE_ADIANTUM &&
filenames_mode == FSCRYPT_MODE_ADIANTUM)
return true;
return false;
@ -125,12 +247,12 @@ extern struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags);
extern const struct dentry_operations fscrypt_d_ops;
extern void __printf(3, 4) __cold
fscrypt_msg(struct super_block *sb, const char *level, const char *fmt, ...);
fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...);
#define fscrypt_warn(sb, fmt, ...) \
fscrypt_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__)
#define fscrypt_err(sb, fmt, ...) \
fscrypt_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__)
#define fscrypt_warn(inode, fmt, ...) \
fscrypt_msg((inode), KERN_WARNING, fmt, ##__VA_ARGS__)
#define fscrypt_err(inode, fmt, ...) \
fscrypt_msg((inode), KERN_ERR, fmt, ##__VA_ARGS__)
#define FSCRYPT_MAX_IV_SIZE 32
@ -155,17 +277,279 @@ extern bool fscrypt_fname_encrypted_size(const struct inode *inode,
u32 orig_len, u32 max_len,
u32 *encrypted_len_ret);
/* keyinfo.c */
/* hkdf.c */
struct fscrypt_hkdf {
struct crypto_shash *hmac_tfm;
};
extern int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key,
unsigned int master_key_size);
/*
* The list of contexts in which fscrypt uses HKDF. These values are used as
* the first byte of the HKDF application-specific info string to guarantee that
* info strings are never repeated between contexts. This ensures that all HKDF
* outputs are unique and cryptographically isolated, i.e. knowledge of one
* output doesn't reveal another.
*/
#define HKDF_CONTEXT_KEY_IDENTIFIER 1
#define HKDF_CONTEXT_PER_FILE_KEY 2
#define HKDF_CONTEXT_DIRECT_KEY 3
#define HKDF_CONTEXT_IV_INO_LBLK_64_KEY 4
extern int fscrypt_hkdf_expand(struct fscrypt_hkdf *hkdf, u8 context,
const u8 *info, unsigned int infolen,
u8 *okm, unsigned int okmlen);
extern void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf);
/* inline_crypt.c */
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
extern bool fscrypt_should_use_inline_encryption(const struct fscrypt_info *ci);
extern int fscrypt_set_inline_crypt_key(struct fscrypt_info *ci,
const u8 *derived_key);
extern void fscrypt_free_inline_crypt_key(struct fscrypt_info *ci);
extern int fscrypt_setup_per_mode_inline_crypt_key(
struct fscrypt_info *ci,
struct fscrypt_master_key *mk);
extern void fscrypt_evict_inline_crypt_keys(struct fscrypt_master_key *mk);
#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
static inline bool fscrypt_should_use_inline_encryption(
const struct fscrypt_info *ci)
{
return false;
}
static inline int fscrypt_set_inline_crypt_key(struct fscrypt_info *ci,
const u8 *derived_key)
{
WARN_ON(1);
return -EOPNOTSUPP;
}
static inline void fscrypt_free_inline_crypt_key(struct fscrypt_info *ci)
{
}
static inline int fscrypt_setup_per_mode_inline_crypt_key(
struct fscrypt_info *ci,
struct fscrypt_master_key *mk)
{
WARN_ON(1);
return -EOPNOTSUPP;
}
static inline void fscrypt_evict_inline_crypt_keys(
struct fscrypt_master_key *mk)
{
}
#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
/* keyring.c */
/*
* fscrypt_master_key_secret - secret key material of an in-use master key
*/
struct fscrypt_master_key_secret {
/*
* For v2 policy keys: HKDF context keyed by this master key.
* For v1 policy keys: not set (hkdf.hmac_tfm == NULL).
*/
struct fscrypt_hkdf hkdf;
/* Size of the raw key in bytes. Set even if ->raw isn't set. */
u32 size;
/* For v1 policy keys: the raw key. Wiped for v2 policy keys. */
u8 raw[FSCRYPT_MAX_KEY_SIZE];
} __randomize_layout;
/*
* fscrypt_master_key - an in-use master key
*
* This represents a master encryption key which has been added to the
* filesystem and can be used to "unlock" the encrypted files which were
* encrypted with it.
*/
struct fscrypt_master_key {
/*
* The secret key material. After FS_IOC_REMOVE_ENCRYPTION_KEY is
* executed, this is wiped and no new inodes can be unlocked with this
* key; however, there may still be inodes in ->mk_decrypted_inodes
* which could not be evicted. As long as some inodes still remain,
* FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or
* FS_IOC_ADD_ENCRYPTION_KEY can add the secret again.
*
* Locking: protected by key->sem (outer) and mk_secret_sem (inner).
* The reason for two locks is that key->sem also protects modifying
* mk_users, which ranks it above the semaphore for the keyring key
* type, which is in turn above page faults (via keyring_read). But
* sometimes filesystems call fscrypt_get_encryption_info() from within
* a transaction, which ranks it below page faults. So we need a
* separate lock which protects mk_secret but not also mk_users.
*/
struct fscrypt_master_key_secret mk_secret;
struct rw_semaphore mk_secret_sem;
/*
* For v1 policy keys: an arbitrary key descriptor which was assigned by
* userspace (->descriptor).
*
* For v2 policy keys: a cryptographic hash of this key (->identifier).
*/
struct fscrypt_key_specifier mk_spec;
/*
* Keyring which contains a key of type 'key_type_fscrypt_user' for each
* user who has added this key. Normally each key will be added by just
* one user, but it's possible that multiple users share a key, and in
* that case we need to keep track of those users so that one user can't
* remove the key before the others want it removed too.
*
* This is NULL for v1 policy keys; those can only be added by root.
*
* Locking: in addition to this keyrings own semaphore, this is
* protected by the master key's key->sem, so we can do atomic
* search+insert. It can also be searched without taking any locks, but
* in that case the returned key may have already been removed.
*/
struct key *mk_users;
/*
* Length of ->mk_decrypted_inodes, plus one if mk_secret is present.
* Once this goes to 0, the master key is removed from ->s_master_keys.
* The 'struct fscrypt_master_key' will continue to live as long as the
* 'struct key' whose payload it is, but we won't let this reference
* count rise again.
*/
refcount_t mk_refcount;
/*
* List of inodes that were unlocked using this key. This allows the
* inodes to be evicted efficiently if the key is removed.
*/
struct list_head mk_decrypted_inodes;
spinlock_t mk_decrypted_inodes_lock;
/* Crypto API transforms for DIRECT_KEY policies, allocated on-demand */
struct crypto_skcipher *mk_direct_tfms[__FSCRYPT_MODE_MAX + 1];
/*
* Crypto API transforms for filesystem-layer implementation of
* IV_INO_LBLK_64 policies, allocated on-demand.
*/
struct crypto_skcipher *mk_iv_ino_lblk_64_tfms[__FSCRYPT_MODE_MAX + 1];
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
/* Raw keys for IV_INO_LBLK_64 policies, allocated on-demand */
u8 *mk_iv_ino_lblk_64_raw_keys[__FSCRYPT_MODE_MAX + 1];
/* The data unit size being used for inline encryption */
unsigned int mk_data_unit_size;
/* The filesystem's block device */
struct block_device *mk_bdev;
#endif
} __randomize_layout;
static inline bool
is_master_key_secret_present(const struct fscrypt_master_key_secret *secret)
{
/*
* The READ_ONCE() is only necessary for fscrypt_drop_inode() and
* fscrypt_key_describe(). These run in atomic context, so they can't
* take ->mk_secret_sem and thus 'secret' can change concurrently which
* would be a data race. But they only need to know whether the secret
* *was* present at the time of check, so READ_ONCE() suffices.
*/
return READ_ONCE(secret->size) != 0;
}
static inline const char *master_key_spec_type(
const struct fscrypt_key_specifier *spec)
{
switch (spec->type) {
case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR:
return "descriptor";
case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER:
return "identifier";
}
return "[unknown]";
}
static inline int master_key_spec_len(const struct fscrypt_key_specifier *spec)
{
switch (spec->type) {
case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR:
return FSCRYPT_KEY_DESCRIPTOR_SIZE;
case FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER:
return FSCRYPT_KEY_IDENTIFIER_SIZE;
}
return 0;
}
extern struct key *
fscrypt_find_master_key(struct super_block *sb,
const struct fscrypt_key_specifier *mk_spec);
extern int fscrypt_verify_key_added(struct super_block *sb,
const u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]);
extern int __init fscrypt_init_keyring(void);
/* keysetup.c */
struct fscrypt_mode {
const char *friendly_name;
const char *cipher_str;
int keysize;
int ivsize;
enum blk_crypto_mode_num blk_crypto_mode;
bool logged_impl_name;
bool needs_essiv;
};
extern void __exit fscrypt_essiv_cleanup(void);
extern struct fscrypt_mode fscrypt_modes[];
static inline bool
fscrypt_mode_supports_direct_key(const struct fscrypt_mode *mode)
{
return mode->ivsize >= offsetofend(union fscrypt_iv, nonce);
}
extern struct crypto_skcipher *
fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key,
const struct inode *inode);
extern int fscrypt_set_derived_key(struct fscrypt_info *ci,
const u8 *derived_key);
/* keysetup_v1.c */
extern void fscrypt_put_direct_key(struct fscrypt_direct_key *dk);
extern int fscrypt_setup_v1_file_key(struct fscrypt_info *ci,
const u8 *raw_master_key);
extern int fscrypt_setup_v1_file_key_via_subscribed_keyrings(
struct fscrypt_info *ci);
/* policy.c */
extern bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
const union fscrypt_policy *policy2);
extern bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
const struct inode *inode);
extern int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
const union fscrypt_context *ctx_u,
int ctx_size);
#endif /* _FSCRYPT_PRIVATE_H */

183
fs/crypto/hkdf.c Normal file
View file

@ -0,0 +1,183 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Implementation of HKDF ("HMAC-based Extract-and-Expand Key Derivation
* Function"), aka RFC 5869. See also the original paper (Krawczyk 2010):
* "Cryptographic Extraction and Key Derivation: The HKDF Scheme".
*
* This is used to derive keys from the fscrypt master keys.
*
* Copyright 2019 Google LLC
*/
#include <crypto/hash.h>
#include <crypto/sha.h>
#include "fscrypt_private.h"
/*
* HKDF supports any unkeyed cryptographic hash algorithm, but fscrypt uses
* SHA-512 because it is reasonably secure and efficient; and since it produces
* a 64-byte digest, deriving an AES-256-XTS key preserves all 64 bytes of
* entropy from the master key and requires only one iteration of HKDF-Expand.
*/
#define HKDF_HMAC_ALG "hmac(sha512)"
#define HKDF_HASHLEN SHA512_DIGEST_SIZE
/*
* HKDF consists of two steps:
*
* 1. HKDF-Extract: extract a pseudorandom key of length HKDF_HASHLEN bytes from
* the input keying material and optional salt.
* 2. HKDF-Expand: expand the pseudorandom key into output keying material of
* any length, parameterized by an application-specific info string.
*
* HKDF-Extract can be skipped if the input is already a pseudorandom key of
* length HKDF_HASHLEN bytes. However, cipher modes other than AES-256-XTS take
* shorter keys, and we don't want to force users of those modes to provide
* unnecessarily long master keys. Thus fscrypt still does HKDF-Extract. No
* salt is used, since fscrypt master keys should already be pseudorandom and
* there's no way to persist a random salt per master key from kernel mode.
*/
/* HKDF-Extract (RFC 5869 section 2.2), unsalted */
static int hkdf_extract(struct crypto_shash *hmac_tfm, const u8 *ikm,
unsigned int ikmlen, u8 prk[HKDF_HASHLEN])
{
static const u8 default_salt[HKDF_HASHLEN];
SHASH_DESC_ON_STACK(desc, hmac_tfm);
int err;
err = crypto_shash_setkey(hmac_tfm, default_salt, HKDF_HASHLEN);
if (err)
return err;
desc->tfm = hmac_tfm;
desc->flags = 0;
err = crypto_shash_digest(desc, ikm, ikmlen, prk);
shash_desc_zero(desc);
return err;
}
/*
* Compute HKDF-Extract using the given master key as the input keying material,
* and prepare an HMAC transform object keyed by the resulting pseudorandom key.
*
* Afterwards, the keyed HMAC transform object can be used for HKDF-Expand many
* times without having to recompute HKDF-Extract each time.
*/
int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key,
unsigned int master_key_size)
{
struct crypto_shash *hmac_tfm;
u8 prk[HKDF_HASHLEN];
int err;
hmac_tfm = crypto_alloc_shash(HKDF_HMAC_ALG, 0, 0);
if (IS_ERR(hmac_tfm)) {
fscrypt_err(NULL, "Error allocating " HKDF_HMAC_ALG ": %ld",
PTR_ERR(hmac_tfm));
return PTR_ERR(hmac_tfm);
}
if (WARN_ON(crypto_shash_digestsize(hmac_tfm) != sizeof(prk))) {
err = -EINVAL;
goto err_free_tfm;
}
err = hkdf_extract(hmac_tfm, master_key, master_key_size, prk);
if (err)
goto err_free_tfm;
err = crypto_shash_setkey(hmac_tfm, prk, sizeof(prk));
if (err)
goto err_free_tfm;
hkdf->hmac_tfm = hmac_tfm;
goto out;
err_free_tfm:
crypto_free_shash(hmac_tfm);
out:
memzero_explicit(prk, sizeof(prk));
return err;
}
/*
* HKDF-Expand (RFC 5869 section 2.3). This expands the pseudorandom key, which
* was already keyed into 'hkdf->hmac_tfm' by fscrypt_init_hkdf(), into 'okmlen'
* bytes of output keying material parameterized by the application-specific
* 'info' of length 'infolen' bytes, prefixed by "fscrypt\0" and the 'context'
* byte. This is thread-safe and may be called by multiple threads in parallel.
*
* ('context' isn't part of the HKDF specification; it's just a prefix fscrypt
* adds to its application-specific info strings to guarantee that it doesn't
* accidentally repeat an info string when using HKDF for different purposes.)
*/
int fscrypt_hkdf_expand(struct fscrypt_hkdf *hkdf, u8 context,
const u8 *info, unsigned int infolen,
u8 *okm, unsigned int okmlen)
{
SHASH_DESC_ON_STACK(desc, hkdf->hmac_tfm);
u8 prefix[9];
unsigned int i;
int err;
const u8 *prev = NULL;
u8 counter = 1;
u8 tmp[HKDF_HASHLEN];
if (WARN_ON(okmlen > 255 * HKDF_HASHLEN))
return -EINVAL;
desc->tfm = hkdf->hmac_tfm;
desc->flags = 0;
memcpy(prefix, "fscrypt\0", 8);
prefix[8] = context;
for (i = 0; i < okmlen; i += HKDF_HASHLEN) {
err = crypto_shash_init(desc);
if (err)
goto out;
if (prev) {
err = crypto_shash_update(desc, prev, HKDF_HASHLEN);
if (err)
goto out;
}
err = crypto_shash_update(desc, prefix, sizeof(prefix));
if (err)
goto out;
err = crypto_shash_update(desc, info, infolen);
if (err)
goto out;
BUILD_BUG_ON(sizeof(counter) != 1);
if (okmlen - i < HKDF_HASHLEN) {
err = crypto_shash_finup(desc, &counter, 1, tmp);
if (err)
goto out;
memcpy(&okm[i], tmp, okmlen - i);
memzero_explicit(tmp, sizeof(tmp));
} else {
err = crypto_shash_finup(desc, &counter, 1, &okm[i]);
if (err)
goto out;
}
counter++;
prev = &okm[i];
}
err = 0;
out:
if (unlikely(err))
memzero_explicit(okm, okmlen); /* so caller doesn't need to */
shash_desc_zero(desc);
return err;
}
void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf)
{
crypto_free_shash(hkdf->hmac_tfm);
}

6
fs/crypto/hooks.c
View file

@ -38,9 +38,9 @@ int fscrypt_file_open(struct inode *inode, struct file *filp)
dir = dget_parent(file_dentry(filp));
if (IS_ENCRYPTED(d_inode(dir)) &&
!fscrypt_has_permitted_context(d_inode(dir), inode)) {
fscrypt_warn(inode->i_sb,
"inconsistent encryption contexts: %lu/%lu",
d_inode(dir)->i_ino, inode->i_ino);
fscrypt_warn(inode,
"Inconsistent encryption context (parent directory: %lu)",
d_inode(dir)->i_ino);
err = -EPERM;
}
dput(dir);

390
fs/crypto/inline_crypt.c Normal file
View file

@ -0,0 +1,390 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Inline encryption support for fscrypt
*
* Copyright 2019 Google LLC
*/
/*
* With "inline encryption", the block layer handles the decryption/encryption
* as part of the bio, instead of the filesystem doing the crypto itself via
* crypto API. See Documentation/block/inline-encryption.rst. fscrypt still
* provides the key and IV to use.
*/
#include <linux/blk-crypto.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/keyslot-manager.h>
#include "fscrypt_private.h"
/* Return true iff inline encryption should be used for this file */
bool fscrypt_should_use_inline_encryption(const struct fscrypt_info *ci)
{
const struct inode *inode = ci->ci_inode;
struct super_block *sb = inode->i_sb;
/* The file must need contents encryption, not filenames encryption */
if (!S_ISREG(inode->i_mode))
return false;
/* blk-crypto must implement the needed encryption algorithm */
if (ci->ci_mode->blk_crypto_mode == BLK_ENCRYPTION_MODE_INVALID)
return false;
/* DIRECT_KEY needs a 24+ byte IV, so it can't work with 8-byte DUNs */
if (fscrypt_is_direct_key_policy(&ci->ci_policy))
return false;
/* The filesystem must be mounted with -o inlinecrypt */
if (!sb->s_cop->inline_crypt_enabled ||
!sb->s_cop->inline_crypt_enabled(sb))
return false;
return true;
}
/* Set a per-file inline encryption key (for passing to blk-crypto) */
int fscrypt_set_inline_crypt_key(struct fscrypt_info *ci, const u8 *derived_key)
{
const struct fscrypt_mode *mode = ci->ci_mode;
const struct super_block *sb = ci->ci_inode->i_sb;
ci->ci_inline_crypt_key = kmemdup(derived_key, mode->keysize, GFP_NOFS);
if (!ci->ci_inline_crypt_key)
return -ENOMEM;
ci->ci_owns_key = true;
return blk_crypto_start_using_mode(mode->blk_crypto_mode,
sb->s_blocksize,
sb->s_bdev->bd_queue);
}
/* Free a per-file inline encryption key and evict it from blk-crypto */
void fscrypt_free_inline_crypt_key(struct fscrypt_info *ci)
{
if (ci->ci_inline_crypt_key != NULL) {
const struct fscrypt_mode *mode = ci->ci_mode;
const struct super_block *sb = ci->ci_inode->i_sb;
blk_crypto_evict_key(sb->s_bdev->bd_queue,
ci->ci_inline_crypt_key,
mode->blk_crypto_mode, sb->s_blocksize);
kzfree(ci->ci_inline_crypt_key);
}
}
/*
* Set up ->inline_crypt_key (for passing to blk-crypto) for inodes which use an
* IV_INO_LBLK_64 encryption policy.
*
* Return: 0 on success, -errno on failure
*/
int fscrypt_setup_per_mode_inline_crypt_key(struct fscrypt_info *ci,
struct fscrypt_master_key *mk)
{
static DEFINE_MUTEX(inline_crypt_setup_mutex);
const struct super_block *sb = ci->ci_inode->i_sb;
struct block_device *bdev = sb->s_bdev;
const struct fscrypt_mode *mode = ci->ci_mode;
const u8 mode_num = mode - fscrypt_modes;
u8 *raw_key;
u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)];
int err;
if (WARN_ON(mode_num > __FSCRYPT_MODE_MAX))
return -EINVAL;
/* pairs with smp_store_release() below */
raw_key = smp_load_acquire(&mk->mk_iv_ino_lblk_64_raw_keys[mode_num]);
if (raw_key) {
err = 0;
goto out;
}
mutex_lock(&inline_crypt_setup_mutex);
raw_key = mk->mk_iv_ino_lblk_64_raw_keys[mode_num];
if (raw_key) {
err = 0;
goto out_unlock;
}
raw_key = kmalloc(mode->keysize, GFP_NOFS);
if (!raw_key) {
err = -ENOMEM;
goto out_unlock;
}
BUILD_BUG_ON(sizeof(mode_num) != 1);
BUILD_BUG_ON(sizeof(sb->s_uuid) != 16);
BUILD_BUG_ON(sizeof(hkdf_info) != 17);
hkdf_info[0] = mode_num;
memcpy(&hkdf_info[1], &sb->s_uuid, sizeof(sb->s_uuid));
err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,
HKDF_CONTEXT_IV_INO_LBLK_64_KEY,
hkdf_info, sizeof(hkdf_info),
raw_key, mode->keysize);
if (err)
goto out_unlock;
err = blk_crypto_start_using_mode(mode->blk_crypto_mode,
sb->s_blocksize, bdev->bd_queue);
if (err)
goto out_unlock;
/*
* When a master key's first inline encryption key is set up, save a
* reference to the filesystem's block device so that the inline
* encryption keys can be evicted when the master key is destroyed.
*/
if (!mk->mk_bdev) {
mk->mk_bdev = bdgrab(bdev);
mk->mk_data_unit_size = sb->s_blocksize;
}
/* pairs with smp_load_acquire() above */
smp_store_release(&mk->mk_iv_ino_lblk_64_raw_keys[mode_num], raw_key);
err = 0;
out_unlock:
mutex_unlock(&inline_crypt_setup_mutex);
out:
if (err == 0) {
ci->ci_inline_crypt_key = raw_key;
/*
* Since each struct fscrypt_master_key belongs to a particular
* filesystem (a struct super_block), there should be only one
* block device, and only one data unit size as it should equal
* the filesystem's blocksize (i.e. s_blocksize).
*/
if (WARN_ON(mk->mk_bdev != bdev))
err = -EINVAL;
if (WARN_ON(mk->mk_data_unit_size != sb->s_blocksize))
err = -EINVAL;
} else {
kzfree(raw_key);
}
return err;
}
/*
* Evict per-mode inline encryption keys from blk-crypto when a master key is
* destroyed.
*/
void fscrypt_evict_inline_crypt_keys(struct fscrypt_master_key *mk)
{
struct block_device *bdev = mk->mk_bdev;
size_t i;
if (!bdev) /* No inline encryption keys? */
return;
for (i = 0; i < ARRAY_SIZE(mk->mk_iv_ino_lblk_64_raw_keys); i++) {
u8 *raw_key = mk->mk_iv_ino_lblk_64_raw_keys[i];
if (raw_key != NULL) {
blk_crypto_evict_key(bdev->bd_queue, raw_key,
fscrypt_modes[i].blk_crypto_mode,
mk->mk_data_unit_size);
kzfree(raw_key);
}
}
bdput(bdev);
}
/**
* fscrypt_inode_uses_inline_crypto - test whether an inode uses inline encryption
* @inode: an inode
*
* Return: true if the inode requires file contents encryption and if the
* encryption should be done in the block layer via blk-crypto rather
* than in the filesystem layer.
*/
bool fscrypt_inode_uses_inline_crypto(const struct inode *inode)
{
return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) &&
inode->i_crypt_info->ci_inline_crypt_key != NULL;
}
EXPORT_SYMBOL_GPL(fscrypt_inode_uses_inline_crypto);
/**
* fscrypt_inode_uses_fs_layer_crypto - test whether an inode uses fs-layer encryption
* @inode: an inode
*
* Return: true if the inode requires file contents encryption and if the
* encryption should be done in the filesystem layer rather than in the
* block layer via blk-crypto.
*/
bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
{
return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) &&
inode->i_crypt_info->ci_inline_crypt_key == NULL;
}
EXPORT_SYMBOL_GPL(fscrypt_inode_uses_fs_layer_crypto);
static inline u64 fscrypt_generate_dun(const struct fscrypt_info *ci,
u64 lblk_num)
{
union fscrypt_iv iv;
fscrypt_generate_iv(&iv, lblk_num, ci);
/*
* fscrypt_should_use_inline_encryption() ensures we never get here if
* more than the first 8 bytes of the IV are nonzero.
*/
BUG_ON(memchr_inv(&iv.raw[8], 0, ci->ci_mode->ivsize - 8));
return le64_to_cpu(iv.lblk_num);
}
/**
* fscrypt_set_bio_crypt_ctx - prepare a file contents bio for inline encryption
* @bio: a bio which will eventually be submitted to the file
* @inode: the file's inode
* @first_lblk: the first file logical block number in the I/O
* @gfp_mask: memory allocation flags
*
* If the contents of the file should be encrypted (or decrypted) with inline
* encryption, then assign the appropriate encryption context to the bio.
*
* Normally the bio should be newly allocated (i.e. no pages added yet), as
* otherwise fscrypt_mergeable_bio() won't work as intended.
*
* The encryption context will be freed automatically when the bio is freed.
*
* Return: 0 on success, -errno on failure. If __GFP_NOFAIL is specified, this
* is guaranteed to succeed.
*/
int fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode,
u64 first_lblk, gfp_t gfp_mask)
{
const struct fscrypt_info *ci = inode->i_crypt_info;
u64 dun;
if (!fscrypt_inode_uses_inline_crypto(inode))
return 0;
dun = fscrypt_generate_dun(ci, first_lblk);
return bio_crypt_set_ctx(bio, ci->ci_inline_crypt_key,
ci->ci_mode->blk_crypto_mode,
dun, inode->i_blkbits, gfp_mask);
}
EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx);
/* Extract the inode and logical block number from a buffer_head. */
static bool bh_get_inode_and_lblk_num(const struct buffer_head *bh,
const struct inode **inode_ret,
u64 *lblk_num_ret)
{
struct page *page = bh->b_page;
const struct address_space *mapping;
const struct inode *inode;
/*
* The ext4 journal (jbd2) can submit a buffer_head it directly created
* for a non-pagecache page. fscrypt doesn't care about these.
*/
mapping = page_mapping(page);
if (!mapping)
return false;
inode = mapping->host;
*inode_ret = inode;
*lblk_num_ret = ((u64)page->index << (PAGE_SHIFT - inode->i_blkbits)) +
(bh_offset(bh) >> inode->i_blkbits);
return true;
}
/**
* fscrypt_set_bio_crypt_ctx_bh - prepare a file contents bio for inline encryption
* @bio: a bio which will eventually be submitted to the file
* @first_bh: the first buffer_head for which I/O will be submitted
* @gfp_mask: memory allocation flags
*
* Same as fscrypt_set_bio_crypt_ctx(), except this takes a buffer_head instead
* of an inode and block number directly.
*
* Return: 0 on success, -errno on failure
*/
int fscrypt_set_bio_crypt_ctx_bh(struct bio *bio,
const struct buffer_head *first_bh,
gfp_t gfp_mask)
{
const struct inode *inode;
u64 first_lblk;
if (!bh_get_inode_and_lblk_num(first_bh, &inode, &first_lblk))
return 0;
return fscrypt_set_bio_crypt_ctx(bio, inode, first_lblk, gfp_mask);
}
EXPORT_SYMBOL_GPL(fscrypt_set_bio_crypt_ctx_bh);
/**
* fscrypt_mergeable_bio - test whether data can be added to a bio
* @bio: the bio being built up
* @inode: the inode for the next part of the I/O
* @next_lblk: the next file logical block number in the I/O
*
* When building a bio which may contain data which should undergo inline
* encryption (or decryption) via fscrypt, filesystems should call this function
* to ensure that the resulting bio contains only logically contiguous data.
* This will return false if the next part of the I/O cannot be merged with the
* bio because either the encryption key would be different or the encryption
* data unit numbers would be discontiguous.
*
* fscrypt_set_bio_crypt_ctx() must have already been called on the bio.
*
* Return: true iff the I/O is mergeable
*/
bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode,
u64 next_lblk)
{
const struct bio_crypt_ctx *bc;
const u8 *next_key;
u64 next_dun;
if (bio_has_crypt_ctx(bio) != fscrypt_inode_uses_inline_crypto(inode))
return false;
if (!bio_has_crypt_ctx(bio))
return true;
bc = bio->bi_crypt_context;
next_key = inode->i_crypt_info->ci_inline_crypt_key;
next_dun = fscrypt_generate_dun(inode->i_crypt_info, next_lblk);
/*
* Comparing the key pointers is good enough, as all I/O for each key
* uses the same pointer. I.e., there's currently no need to support
* merging requests where the keys are the same but the pointers differ.
*/
return next_key == bc->raw_key &&
next_dun == bc->data_unit_num +
(bio_sectors(bio) >>
(bc->data_unit_size_bits - SECTOR_SHIFT));
}
EXPORT_SYMBOL_GPL(fscrypt_mergeable_bio);
/**
* fscrypt_mergeable_bio_bh - test whether data can be added to a bio
* @bio: the bio being built up
* @next_bh: the next buffer_head for which I/O will be submitted
*
* Same as fscrypt_mergeable_bio(), except this takes a buffer_head instead of
* an inode and block number directly.
*
* Return: true iff the I/O is mergeable
*/
bool fscrypt_mergeable_bio_bh(struct bio *bio,
const struct buffer_head *next_bh)
{
const struct inode *inode;
u64 next_lblk;
if (!bh_get_inode_and_lblk_num(next_bh, &inode, &next_lblk))
return !bio_has_crypt_ctx(bio);
return fscrypt_mergeable_bio(bio, inode, next_lblk);
}
EXPORT_SYMBOL_GPL(fscrypt_mergeable_bio_bh);

612
fs/crypto/keyinfo.c
View file

@ -1,612 +0,0 @@
// SPDX-License-Identifier: GPL-2.0
/*
* key management facility for FS encryption support.
*
* Copyright (C) 2015, Google, Inc.
*
* This contains encryption key functions.
*
* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
*/
#include <keys/user-type.h>
#include <linux/hashtable.h>
#include <linux/scatterlist.h>
#include <crypto/aes.h>
#include <crypto/algapi.h>
#include <crypto/sha.h>
#include <crypto/skcipher.h>
#include "fscrypt_private.h"
static struct crypto_shash *essiv_hash_tfm;
/* Table of keys referenced by FS_POLICY_FLAG_DIRECT_KEY policies */
static DEFINE_HASHTABLE(fscrypt_master_keys, 6); /* 6 bits = 64 buckets */
static DEFINE_SPINLOCK(fscrypt_master_keys_lock);
/*
* Key derivation function. This generates the derived key by encrypting the
* master key with AES-128-ECB using the inode's nonce as the AES key.
*
* The master key must be at least as long as the derived key. If the master
* key is longer, then only the first 'derived_keysize' bytes are used.
*/
static int derive_key_aes(const u8 *master_key,
const struct fscrypt_context *ctx,
u8 *derived_key, unsigned int derived_keysize)
{
int res = 0;
struct skcipher_request *req = NULL;
DECLARE_CRYPTO_WAIT(wait);
struct scatterlist src_sg, dst_sg;
struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
if (IS_ERR(tfm)) {
res = PTR_ERR(tfm);
tfm = NULL;
goto out;
}
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
req = skcipher_request_alloc(tfm, GFP_NOFS);
if (!req) {
res = -ENOMEM;
goto out;
}
skcipher_request_set_callback(req,
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &wait);
res = crypto_skcipher_setkey(tfm, ctx->nonce, sizeof(ctx->nonce));
if (res < 0)
goto out;
sg_init_one(&src_sg, master_key, derived_keysize);
sg_init_one(&dst_sg, derived_key, derived_keysize);
skcipher_request_set_crypt(req, &src_sg, &dst_sg, derived_keysize,
NULL);
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
out:
skcipher_request_free(req);
crypto_free_skcipher(tfm);
return res;
}
/*
* Search the current task's subscribed keyrings for a "logon" key with
* description prefix:descriptor, and if found acquire a read lock on it and
* return a pointer to its validated payload in *payload_ret.
*/
static struct key *
find_and_lock_process_key(const char *prefix,
const u8 descriptor[FS_KEY_DESCRIPTOR_SIZE],
unsigned int min_keysize,
const struct fscrypt_key **payload_ret)
{
char *description;
struct key *key;
const struct user_key_payload *ukp;
const struct fscrypt_key *payload;
description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
FS_KEY_DESCRIPTOR_SIZE, descriptor);
if (!description)
return ERR_PTR(-ENOMEM);
key = request_key(&key_type_logon, description, NULL);
kfree(description);
if (IS_ERR(key))
return key;
down_read(&key->sem);
ukp = user_key_payload_locked(key);
if (!ukp) /* was the key revoked before we acquired its semaphore? */
goto invalid;
payload = (const struct fscrypt_key *)ukp->data;
if (ukp->datalen != sizeof(struct fscrypt_key) ||
payload->size < 1 || payload->size > FS_MAX_KEY_SIZE) {
fscrypt_warn(NULL,
"key with description '%s' has invalid payload",
key->description);
goto invalid;
}
if (payload->size < min_keysize) {
fscrypt_warn(NULL,
"key with description '%s' is too short (got %u bytes, need %u+ bytes)",
key->description, payload->size, min_keysize);
goto invalid;
}
*payload_ret = payload;
return key;
invalid:
up_read(&key->sem);
key_put(key);
return ERR_PTR(-ENOKEY);
}
static struct fscrypt_mode available_modes[] = {
[FS_ENCRYPTION_MODE_AES_256_XTS] = {
.friendly_name = "AES-256-XTS",
.cipher_str = "xts(aes)",
.keysize = 64,
.ivsize = 16,
},
[FS_ENCRYPTION_MODE_AES_256_CTS] = {
.friendly_name = "AES-256-CTS-CBC",
.cipher_str = "cts(cbc(aes))",
.keysize = 32,
.ivsize = 16,
},
[FS_ENCRYPTION_MODE_AES_128_CBC] = {
.friendly_name = "AES-128-CBC",
.cipher_str = "cbc(aes)",
.keysize = 16,
.ivsize = 16,
.needs_essiv = true,
},
[FS_ENCRYPTION_MODE_AES_128_CTS] = {
.friendly_name = "AES-128-CTS-CBC",
.cipher_str = "cts(cbc(aes))",
.keysize = 16,
.ivsize = 16,
},
[FS_ENCRYPTION_MODE_ADIANTUM] = {
.friendly_name = "Adiantum",
.cipher_str = "adiantum(xchacha12,aes)",
.keysize = 32,
.ivsize = 32,
},
};
static struct fscrypt_mode *
select_encryption_mode(const struct fscrypt_info *ci, const struct inode *inode)
{
if (!fscrypt_valid_enc_modes(ci->ci_data_mode, ci->ci_filename_mode)) {
fscrypt_warn(inode->i_sb,
"inode %lu uses unsupported encryption modes (contents mode %d, filenames mode %d)",
inode->i_ino, ci->ci_data_mode,
ci->ci_filename_mode);
return ERR_PTR(-EINVAL);
}
if (S_ISREG(inode->i_mode))
return &available_modes[ci->ci_data_mode];
if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
return &available_modes[ci->ci_filename_mode];
WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
inode->i_ino, (inode->i_mode & S_IFMT));
return ERR_PTR(-EINVAL);
}
/* Find the master key, then derive the inode's actual encryption key */
static int find_and_derive_key(const struct inode *inode,
const struct fscrypt_context *ctx,
u8 *derived_key, const struct fscrypt_mode *mode)
{
struct key *key;
const struct fscrypt_key *payload;
int err;
key = find_and_lock_process_key(FS_KEY_DESC_PREFIX,
ctx->master_key_descriptor,
mode->keysize, &payload);
if (key == ERR_PTR(-ENOKEY) && inode->i_sb->s_cop->key_prefix) {
key = find_and_lock_process_key(inode->i_sb->s_cop->key_prefix,
ctx->master_key_descriptor,
mode->keysize, &payload);
}
if (IS_ERR(key))
return PTR_ERR(key);
if (ctx->flags & FS_POLICY_FLAG_DIRECT_KEY) {
if (mode->ivsize < offsetofend(union fscrypt_iv, nonce)) {
fscrypt_warn(inode->i_sb,
"direct key mode not allowed with %s",
mode->friendly_name);
err = -EINVAL;
} else if (ctx->contents_encryption_mode !=
ctx->filenames_encryption_mode) {
fscrypt_warn(inode->i_sb,
"direct key mode not allowed with different contents and filenames modes");
err = -EINVAL;
} else {
memcpy(derived_key, payload->raw, mode->keysize);
err = 0;
}
} else {
err = derive_key_aes(payload->raw, ctx, derived_key,
mode->keysize);
}
up_read(&key->sem);
key_put(key);
return err;
}
/* Allocate and key a symmetric cipher object for the given encryption mode */
static struct crypto_skcipher *
allocate_skcipher_for_mode(struct fscrypt_mode *mode, const u8 *raw_key,
const struct inode *inode)
{
struct crypto_skcipher *tfm;
int err;
tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0);
if (IS_ERR(tfm)) {
fscrypt_warn(inode->i_sb,
"error allocating '%s' transform for inode %lu: %ld",
mode->cipher_str, inode->i_ino, PTR_ERR(tfm));
return tfm;
}
if (unlikely(!mode->logged_impl_name)) {
/*
* fscrypt performance can vary greatly depending on which
* crypto algorithm implementation is used. Help people debug
* performance problems by logging the ->cra_driver_name the
* first time a mode is used. Note that multiple threads can
* race here, but it doesn't really matter.
*/
mode->logged_impl_name = true;
pr_info("fscrypt: %s using implementation \"%s\"\n",
mode->friendly_name,
crypto_skcipher_alg(tfm)->base.cra_driver_name);
}
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize);
if (err)
goto err_free_tfm;
return tfm;
err_free_tfm:
crypto_free_skcipher(tfm);
return ERR_PTR(err);
}
/* Master key referenced by FS_POLICY_FLAG_DIRECT_KEY policy */
struct fscrypt_master_key {
struct hlist_node mk_node;
refcount_t mk_refcount;
const struct fscrypt_mode *mk_mode;
struct crypto_skcipher *mk_ctfm;
u8 mk_descriptor[FS_KEY_DESCRIPTOR_SIZE];
u8 mk_raw[FS_MAX_KEY_SIZE];
};
static void free_master_key(struct fscrypt_master_key *mk)
{
if (mk) {
crypto_free_skcipher(mk->mk_ctfm);
kzfree(mk);
}
}
static void put_master_key(struct fscrypt_master_key *mk)
{
if (!refcount_dec_and_lock(&mk->mk_refcount, &fscrypt_master_keys_lock))
return;
hash_del(&mk->mk_node);
spin_unlock(&fscrypt_master_keys_lock);
free_master_key(mk);
}
/*
* Find/insert the given master key into the fscrypt_master_keys table. If
* found, it is returned with elevated refcount, and 'to_insert' is freed if
* non-NULL. If not found, 'to_insert' is inserted and returned if it's
* non-NULL; otherwise NULL is returned.
*/
static struct fscrypt_master_key *
find_or_insert_master_key(struct fscrypt_master_key *to_insert,
const u8 *raw_key, const struct fscrypt_mode *mode,
const struct fscrypt_info *ci)
{
unsigned long hash_key;
struct fscrypt_master_key *mk;
/*
* Careful: to avoid potentially leaking secret key bytes via timing
* information, we must key the hash table by descriptor rather than by
* raw key, and use crypto_memneq() when comparing raw keys.
*/
BUILD_BUG_ON(sizeof(hash_key) > FS_KEY_DESCRIPTOR_SIZE);
memcpy(&hash_key, ci->ci_master_key_descriptor, sizeof(hash_key));
spin_lock(&fscrypt_master_keys_lock);
hash_for_each_possible(fscrypt_master_keys, mk, mk_node, hash_key) {
if (memcmp(ci->ci_master_key_descriptor, mk->mk_descriptor,
FS_KEY_DESCRIPTOR_SIZE) != 0)
continue;
if (mode != mk->mk_mode)
continue;
if (crypto_memneq(raw_key, mk->mk_raw, mode->keysize))
continue;
/* using existing tfm with same (descriptor, mode, raw_key) */
refcount_inc(&mk->mk_refcount);
spin_unlock(&fscrypt_master_keys_lock);
free_master_key(to_insert);
return mk;
}
if (to_insert)
hash_add(fscrypt_master_keys, &to_insert->mk_node, hash_key);
spin_unlock(&fscrypt_master_keys_lock);
return to_insert;
}
/* Prepare to encrypt directly using the master key in the given mode */
static struct fscrypt_master_key *
fscrypt_get_master_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode,
const u8 *raw_key, const struct inode *inode)
{
struct fscrypt_master_key *mk;
int err;
/* Is there already a tfm for this key? */
mk = find_or_insert_master_key(NULL, raw_key, mode, ci);
if (mk)
return mk;
/* Nope, allocate one. */
mk = kzalloc(sizeof(*mk), GFP_NOFS);
if (!mk)
return ERR_PTR(-ENOMEM);
refcount_set(&mk->mk_refcount, 1);
mk->mk_mode = mode;
mk->mk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
if (IS_ERR(mk->mk_ctfm)) {
err = PTR_ERR(mk->mk_ctfm);
mk->mk_ctfm = NULL;
goto err_free_mk;
}
memcpy(mk->mk_descriptor, ci->ci_master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE);
memcpy(mk->mk_raw, raw_key, mode->keysize);
return find_or_insert_master_key(mk, raw_key, mode, ci);
err_free_mk:
free_master_key(mk);
return ERR_PTR(err);
}
static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt)
{
struct crypto_shash *tfm = READ_ONCE(essiv_hash_tfm);
/* init hash transform on demand */
if (unlikely(!tfm)) {
struct crypto_shash *prev_tfm;
tfm = crypto_alloc_shash("sha256", 0, 0);
if (IS_ERR(tfm)) {
fscrypt_warn(NULL,
"error allocating SHA-256 transform: %ld",
PTR_ERR(tfm));
return PTR_ERR(tfm);
}
prev_tfm = cmpxchg(&essiv_hash_tfm, NULL, tfm);
if (prev_tfm) {
crypto_free_shash(tfm);
tfm = prev_tfm;
}
}
{
SHASH_DESC_ON_STACK(desc, tfm);
desc->tfm = tfm;
desc->flags = 0;
return crypto_shash_digest(desc, key, keysize, salt);
}
}
static int init_essiv_generator(struct fscrypt_info *ci, const u8 *raw_key,
int keysize)
{
int err;
struct crypto_cipher *essiv_tfm;
u8 salt[SHA256_DIGEST_SIZE];
essiv_tfm = crypto_alloc_cipher("aes", 0, 0);
if (IS_ERR(essiv_tfm))
return PTR_ERR(essiv_tfm);
ci->ci_essiv_tfm = essiv_tfm;
err = derive_essiv_salt(raw_key, keysize, salt);
if (err)
goto out;
/*
* Using SHA256 to derive the salt/key will result in AES-256 being
* used for IV generation. File contents encryption will still use the
* configured keysize (AES-128) nevertheless.
*/
err = crypto_cipher_setkey(essiv_tfm, salt, sizeof(salt));
if (err)
goto out;
out:
memzero_explicit(salt, sizeof(salt));
return err;
}
void __exit fscrypt_essiv_cleanup(void)
{
crypto_free_shash(essiv_hash_tfm);
}
/*
* Given the encryption mode and key (normally the derived key, but for
* FS_POLICY_FLAG_DIRECT_KEY mode it's the master key), set up the inode's
* symmetric cipher transform object(s).
*/
static int setup_crypto_transform(struct fscrypt_info *ci,
struct fscrypt_mode *mode,
const u8 *raw_key, const struct inode *inode)
{
struct fscrypt_master_key *mk;
struct crypto_skcipher *ctfm;
int err;
if (ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY) {
mk = fscrypt_get_master_key(ci, mode, raw_key, inode);
if (IS_ERR(mk))
return PTR_ERR(mk);
ctfm = mk->mk_ctfm;
} else {
mk = NULL;
ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
if (IS_ERR(ctfm))
return PTR_ERR(ctfm);
}
ci->ci_master_key = mk;
ci->ci_ctfm = ctfm;
if (mode->needs_essiv) {
/* ESSIV implies 16-byte IVs which implies !DIRECT_KEY */
WARN_ON(mode->ivsize != AES_BLOCK_SIZE);
WARN_ON(ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY);
err = init_essiv_generator(ci, raw_key, mode->keysize);
if (err) {
fscrypt_warn(inode->i_sb,
"error initializing ESSIV generator for inode %lu: %d",
inode->i_ino, err);
return err;
}
}
return 0;
}
static void put_crypt_info(struct fscrypt_info *ci)
{
if (!ci)
return;
if (ci->ci_master_key) {
put_master_key(ci->ci_master_key);
} else {
crypto_free_skcipher(ci->ci_ctfm);
crypto_free_cipher(ci->ci_essiv_tfm);
}
kmem_cache_free(fscrypt_info_cachep, ci);
}
int fscrypt_get_encryption_info(struct inode *inode)
{
struct fscrypt_info *crypt_info;
struct fscrypt_context ctx;
struct fscrypt_mode *mode;
u8 *raw_key = NULL;
int res;
if (fscrypt_has_encryption_key(inode))
return 0;
res = fscrypt_initialize(inode->i_sb->s_cop->flags);
if (res)
return res;
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res < 0) {
if (!fscrypt_dummy_context_enabled(inode) ||
IS_ENCRYPTED(inode))
return res;
/* Fake up a context for an unencrypted directory */
memset(&ctx, 0, sizeof(ctx));
ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
} else if (res != sizeof(ctx)) {
return -EINVAL;
}
if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
return -EINVAL;
if (ctx.flags & ~FS_POLICY_FLAGS_VALID)
return -EINVAL;
crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS);
if (!crypt_info)
return -ENOMEM;
crypt_info->ci_flags = ctx.flags;
crypt_info->ci_data_mode = ctx.contents_encryption_mode;
crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
memcpy(crypt_info->ci_master_key_descriptor, ctx.master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE);
memcpy(crypt_info->ci_nonce, ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
mode = select_encryption_mode(crypt_info, inode);
if (IS_ERR(mode)) {
res = PTR_ERR(mode);
goto out;
}
WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
crypt_info->ci_mode = mode;
/*
* This cannot be a stack buffer because it may be passed to the
* scatterlist crypto API as part of key derivation.
*/
res = -ENOMEM;
raw_key = kmalloc(mode->keysize, GFP_NOFS);
if (!raw_key)
goto out;
res = find_and_derive_key(inode, &ctx, raw_key, mode);
if (res)
goto out;
res = setup_crypto_transform(crypt_info, mode, raw_key, inode);
if (res)
goto out;
if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL)
crypt_info = NULL;
out:
if (res == -ENOKEY)
res = 0;
put_crypt_info(crypt_info);
kzfree(raw_key);
return res;
}
EXPORT_SYMBOL(fscrypt_get_encryption_info);
/**
* fscrypt_put_encryption_info - free most of an inode's fscrypt data
*
* Free the inode's fscrypt_info. Filesystems must call this when the inode is
* being evicted. An RCU grace period need not have elapsed yet.
*/
void fscrypt_put_encryption_info(struct inode *inode)
{
put_crypt_info(inode->i_crypt_info);
inode->i_crypt_info = NULL;
}
EXPORT_SYMBOL(fscrypt_put_encryption_info);
/**
* fscrypt_free_inode - free an inode's fscrypt data requiring RCU delay
*
* Free the inode's cached decrypted symlink target, if any. Filesystems must
* call this after an RCU grace period, just before they free the inode.
*/
void fscrypt_free_inode(struct inode *inode)
{
if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) {
kfree(inode->i_link);
inode->i_link = NULL;
}
}
EXPORT_SYMBOL(fscrypt_free_inode);

1010
fs/crypto/keyring.c Normal file
View file

File diff suppressed because it is too large Load diff

537
fs/crypto/keysetup.c Normal file
View file

@ -0,0 +1,537 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Key setup facility for FS encryption support.
*
* Copyright (C) 2015, Google, Inc.
*
* Originally written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar.
* Heavily modified since then.
*/
#include <crypto/skcipher.h>
#include <linux/key.h>
#include "fscrypt_private.h"
struct fscrypt_mode fscrypt_modes[] = {
[FSCRYPT_MODE_AES_256_XTS] = {
.friendly_name = "AES-256-XTS",
.cipher_str = "xts(aes)",
.keysize = 64,
.ivsize = 16,
.blk_crypto_mode = BLK_ENCRYPTION_MODE_AES_256_XTS,
},
[FSCRYPT_MODE_AES_256_CTS] = {
.friendly_name = "AES-256-CTS-CBC",
.cipher_str = "cts(cbc(aes))",
.keysize = 32,
.ivsize = 16,
},
[FSCRYPT_MODE_AES_128_CBC] = {
.friendly_name = "AES-128-CBC-ESSIV",
.cipher_str = "essiv(cbc(aes),sha256)",
.keysize = 16,
.ivsize = 16,
},
[FSCRYPT_MODE_AES_128_CTS] = {
.friendly_name = "AES-128-CTS-CBC",
.cipher_str = "cts(cbc(aes))",
.keysize = 16,
.ivsize = 16,
},
[FSCRYPT_MODE_ADIANTUM] = {
.friendly_name = "Adiantum",
.cipher_str = "adiantum(xchacha12,aes)",
.keysize = 32,
.ivsize = 32,
},
};
static struct fscrypt_mode *
select_encryption_mode(const union fscrypt_policy *policy,
const struct inode *inode)
{
if (S_ISREG(inode->i_mode))
return &fscrypt_modes[fscrypt_policy_contents_mode(policy)];
if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
return &fscrypt_modes[fscrypt_policy_fnames_mode(policy)];
WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
inode->i_ino, (inode->i_mode & S_IFMT));
return ERR_PTR(-EINVAL);
}
/* Create a symmetric cipher object for the given encryption mode and key */
struct crypto_skcipher *fscrypt_allocate_skcipher(struct fscrypt_mode *mode,
const u8 *raw_key,
const struct inode *inode)
{
struct crypto_skcipher *tfm;
int err;
tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0);
if (IS_ERR(tfm)) {
if (PTR_ERR(tfm) == -ENOENT) {
fscrypt_warn(inode,
"Missing crypto API support for %s (API name: \"%s\")",
mode->friendly_name, mode->cipher_str);
return ERR_PTR(-ENOPKG);
}
fscrypt_err(inode, "Error allocating '%s' transform: %ld",
mode->cipher_str, PTR_ERR(tfm));
return tfm;
}
if (unlikely(!mode->logged_impl_name)) {
/*
* fscrypt performance can vary greatly depending on which
* crypto algorithm implementation is used. Help people debug
* performance problems by logging the ->cra_driver_name the
* first time a mode is used. Note that multiple threads can
* race here, but it doesn't really matter.
*/
mode->logged_impl_name = true;
pr_info("fscrypt: %s using implementation \"%s\"\n",
mode->friendly_name,
crypto_skcipher_alg(tfm)->base.cra_driver_name);
}
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize);
if (err)
goto err_free_tfm;
return tfm;
err_free_tfm:
crypto_free_skcipher(tfm);
return ERR_PTR(err);
}
/* Given the per-file key, set up the file's crypto transform object */
int fscrypt_set_derived_key(struct fscrypt_info *ci, const u8 *derived_key)
{
struct crypto_skcipher *tfm;
if (fscrypt_should_use_inline_encryption(ci))
return fscrypt_set_inline_crypt_key(ci, derived_key);
tfm = fscrypt_allocate_skcipher(ci->ci_mode, derived_key, ci->ci_inode);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
ci->ci_ctfm = tfm;
ci->ci_owns_key = true;
return 0;
}
static int setup_per_mode_key(struct fscrypt_info *ci,
struct fscrypt_master_key *mk,
struct crypto_skcipher **tfms,
u8 hkdf_context, bool include_fs_uuid)
{
const struct inode *inode = ci->ci_inode;
const struct super_block *sb = inode->i_sb;
struct fscrypt_mode *mode = ci->ci_mode;
const u8 mode_num = mode - fscrypt_modes;
struct crypto_skcipher *tfm, *prev_tfm;
u8 mode_key[FSCRYPT_MAX_KEY_SIZE];
u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)];
unsigned int hkdf_infolen = 0;
int err;
if (WARN_ON(mode_num > __FSCRYPT_MODE_MAX))
return -EINVAL;
/* pairs with cmpxchg() below */
tfm = READ_ONCE(tfms[mode_num]);
if (likely(tfm != NULL))
goto done;
BUILD_BUG_ON(sizeof(mode_num) != 1);
BUILD_BUG_ON(sizeof(sb->s_uuid) != 16);
BUILD_BUG_ON(sizeof(hkdf_info) != 17);
hkdf_info[hkdf_infolen++] = mode_num;
if (include_fs_uuid) {
memcpy(&hkdf_info[hkdf_infolen], &sb->s_uuid,
sizeof(sb->s_uuid));
hkdf_infolen += sizeof(sb->s_uuid);
}
err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,
hkdf_context, hkdf_info, hkdf_infolen,
mode_key, mode->keysize);
if (err)
return err;
tfm = fscrypt_allocate_skcipher(mode, mode_key, inode);
memzero_explicit(mode_key, mode->keysize);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
/* pairs with READ_ONCE() above */
prev_tfm = cmpxchg(&tfms[mode_num], NULL, tfm);
if (prev_tfm != NULL) {
crypto_free_skcipher(tfm);
tfm = prev_tfm;
}
done:
ci->ci_ctfm = tfm;
return 0;
}
static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci,
struct fscrypt_master_key *mk)
{
u8 derived_key[FSCRYPT_MAX_KEY_SIZE];
int err;
if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {
/*
* DIRECT_KEY: instead of deriving per-file keys, the per-file
* nonce will be included in all the IVs. But unlike v1
* policies, for v2 policies in this case we don't encrypt with
* the master key directly but rather derive a per-mode key.
* This ensures that the master key is consistently used only
* for HKDF, avoiding key reuse issues.
*/
if (!fscrypt_mode_supports_direct_key(ci->ci_mode)) {
fscrypt_warn(ci->ci_inode,
"Direct key flag not allowed with %s",
ci->ci_mode->friendly_name);
return -EINVAL;
}
return setup_per_mode_key(ci, mk, mk->mk_direct_tfms,
HKDF_CONTEXT_DIRECT_KEY, false);
} else if (ci->ci_policy.v2.flags &
FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) {
/*
* IV_INO_LBLK_64: encryption keys are derived from (master_key,
* mode_num, filesystem_uuid), and inode number is included in
* the IVs. This format is optimized for use with inline
* encryption hardware compliant with the UFS or eMMC standards.
*/
if (fscrypt_should_use_inline_encryption(ci))
return fscrypt_setup_per_mode_inline_crypt_key(ci, mk);
return setup_per_mode_key(ci, mk, mk->mk_iv_ino_lblk_64_tfms,
HKDF_CONTEXT_IV_INO_LBLK_64_KEY,
true);
}
err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,
HKDF_CONTEXT_PER_FILE_KEY,
ci->ci_nonce, FS_KEY_DERIVATION_NONCE_SIZE,
derived_key, ci->ci_mode->keysize);
if (err)
return err;
err = fscrypt_set_derived_key(ci, derived_key);
memzero_explicit(derived_key, ci->ci_mode->keysize);
return err;
}
/*
* Find the master key, then set up the inode's actual encryption key.
*
* If the master key is found in the filesystem-level keyring, then the
* corresponding 'struct key' is returned in *master_key_ret with
* ->mk_secret_sem read-locked. This is needed to ensure that only one task
* links the fscrypt_info into ->mk_decrypted_inodes (as multiple tasks may race
* to create an fscrypt_info for the same inode), and to synchronize the master
* key being removed with a new inode starting to use it.
*/
static int setup_file_encryption_key(struct fscrypt_info *ci,
struct key **master_key_ret)
{
struct key *key;
struct fscrypt_master_key *mk = NULL;
struct fscrypt_key_specifier mk_spec;
int err;
switch (ci->ci_policy.version) {
case FSCRYPT_POLICY_V1:
mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
memcpy(mk_spec.u.descriptor,
ci->ci_policy.v1.master_key_descriptor,
FSCRYPT_KEY_DESCRIPTOR_SIZE);
break;
case FSCRYPT_POLICY_V2:
mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
memcpy(mk_spec.u.identifier,
ci->ci_policy.v2.master_key_identifier,
FSCRYPT_KEY_IDENTIFIER_SIZE);
break;
default:
WARN_ON(1);
return -EINVAL;
}
key = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec);
if (IS_ERR(key)) {
if (key != ERR_PTR(-ENOKEY) ||
ci->ci_policy.version != FSCRYPT_POLICY_V1)
return PTR_ERR(key);
/*
* As a legacy fallback for v1 policies, search for the key in
* the current task's subscribed keyrings too. Don't move this
* to before the search of ->s_master_keys, since users
* shouldn't be able to override filesystem-level keys.
*/
return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci);
}
mk = key->payload.data[0];
down_read(&mk->mk_secret_sem);
/* Has the secret been removed (via FS_IOC_REMOVE_ENCRYPTION_KEY)? */
if (!is_master_key_secret_present(&mk->mk_secret)) {
err = -ENOKEY;
goto out_release_key;
}
/*
* Require that the master key be at least as long as the derived key.
* Otherwise, the derived key cannot possibly contain as much entropy as
* that required by the encryption mode it will be used for. For v1
* policies it's also required for the KDF to work at all.
*/
if (mk->mk_secret.size < ci->ci_mode->keysize) {
fscrypt_warn(NULL,
"key with %s %*phN is too short (got %u bytes, need %u+ bytes)",
master_key_spec_type(&mk_spec),
master_key_spec_len(&mk_spec), (u8 *)&mk_spec.u,
mk->mk_secret.size, ci->ci_mode->keysize);
err = -ENOKEY;
goto out_release_key;
}
switch (ci->ci_policy.version) {
case FSCRYPT_POLICY_V1:
err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw);
break;
case FSCRYPT_POLICY_V2:
err = fscrypt_setup_v2_file_key(ci, mk);
break;
default:
WARN_ON(1);
err = -EINVAL;
break;
}
if (err)
goto out_release_key;
*master_key_ret = key;
return 0;
out_release_key:
up_read(&mk->mk_secret_sem);
key_put(key);
return err;
}
static void put_crypt_info(struct fscrypt_info *ci)
{
struct key *key;
if (!ci)
return;
if (ci->ci_direct_key)
fscrypt_put_direct_key(ci->ci_direct_key);
else if (ci->ci_owns_key) {
crypto_free_skcipher(ci->ci_ctfm);
fscrypt_free_inline_crypt_key(ci);
}
key = ci->ci_master_key;
if (key) {
struct fscrypt_master_key *mk = key->payload.data[0];
/*
* Remove this inode from the list of inodes that were unlocked
* with the master key.
*
* In addition, if we're removing the last inode from a key that
* already had its secret removed, invalidate the key so that it
* gets removed from ->s_master_keys.
*/
spin_lock(&mk->mk_decrypted_inodes_lock);
list_del(&ci->ci_master_key_link);
spin_unlock(&mk->mk_decrypted_inodes_lock);
if (refcount_dec_and_test(&mk->mk_refcount))
key_invalidate(key);
key_put(key);
}
memzero_explicit(ci, sizeof(*ci));
kmem_cache_free(fscrypt_info_cachep, ci);
}
int fscrypt_get_encryption_info(struct inode *inode)
{
struct fscrypt_info *crypt_info;
union fscrypt_context ctx;
struct fscrypt_mode *mode;
struct key *master_key = NULL;
int res;
if (fscrypt_has_encryption_key(inode))
return 0;
res = fscrypt_initialize(inode->i_sb->s_cop->flags);
if (res)
return res;
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res < 0) {
if (!fscrypt_dummy_context_enabled(inode) ||
IS_ENCRYPTED(inode)) {
fscrypt_warn(inode,
"Error %d getting encryption context",
res);
return res;
}
/* Fake up a context for an unencrypted directory */
memset(&ctx, 0, sizeof(ctx));
ctx.version = FSCRYPT_CONTEXT_V1;
ctx.v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
ctx.v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
memset(ctx.v1.master_key_descriptor, 0x42,
FSCRYPT_KEY_DESCRIPTOR_SIZE);
res = sizeof(ctx.v1);
}
crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS);
if (!crypt_info)
return -ENOMEM;
crypt_info->ci_inode = inode;
res = fscrypt_policy_from_context(&crypt_info->ci_policy, &ctx, res);
if (res) {
fscrypt_warn(inode,
"Unrecognized or corrupt encryption context");
goto out;
}
switch (ctx.version) {
case FSCRYPT_CONTEXT_V1:
memcpy(crypt_info->ci_nonce, ctx.v1.nonce,
FS_KEY_DERIVATION_NONCE_SIZE);
break;
case FSCRYPT_CONTEXT_V2:
memcpy(crypt_info->ci_nonce, ctx.v2.nonce,
FS_KEY_DERIVATION_NONCE_SIZE);
break;
default:
WARN_ON(1);
res = -EINVAL;
goto out;
}
if (!fscrypt_supported_policy(&crypt_info->ci_policy, inode)) {
res = -EINVAL;
goto out;
}
mode = select_encryption_mode(&crypt_info->ci_policy, inode);
if (IS_ERR(mode)) {
res = PTR_ERR(mode);
goto out;
}
WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
crypt_info->ci_mode = mode;
res = setup_file_encryption_key(crypt_info, &master_key);
if (res)
goto out;
if (cmpxchg_release(&inode->i_crypt_info, NULL, crypt_info) == NULL) {
if (master_key) {
struct fscrypt_master_key *mk =
master_key->payload.data[0];
refcount_inc(&mk->mk_refcount);
crypt_info->ci_master_key = key_get(master_key);
spin_lock(&mk->mk_decrypted_inodes_lock);
list_add(&crypt_info->ci_master_key_link,
&mk->mk_decrypted_inodes);
spin_unlock(&mk->mk_decrypted_inodes_lock);
}
crypt_info = NULL;
}
res = 0;
out:
if (master_key) {
struct fscrypt_master_key *mk = master_key->payload.data[0];
up_read(&mk->mk_secret_sem);
key_put(master_key);
}
if (res == -ENOKEY)
res = 0;
put_crypt_info(crypt_info);
return res;
}
EXPORT_SYMBOL(fscrypt_get_encryption_info);
/**
* fscrypt_put_encryption_info - free most of an inode's fscrypt data
*
* Free the inode's fscrypt_info. Filesystems must call this when the inode is
* being evicted. An RCU grace period need not have elapsed yet.
*/
void fscrypt_put_encryption_info(struct inode *inode)
{
put_crypt_info(inode->i_crypt_info);
inode->i_crypt_info = NULL;
}
EXPORT_SYMBOL(fscrypt_put_encryption_info);
/**
* fscrypt_free_inode - free an inode's fscrypt data requiring RCU delay
*
* Free the inode's cached decrypted symlink target, if any. Filesystems must
* call this after an RCU grace period, just before they free the inode.
*/
void fscrypt_free_inode(struct inode *inode)
{
if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) {
kfree(inode->i_link);
inode->i_link = NULL;
}
}
EXPORT_SYMBOL(fscrypt_free_inode);
/**
* fscrypt_drop_inode - check whether the inode's master key has been removed
*
* Filesystems supporting fscrypt must call this from their ->drop_inode()
* method so that encrypted inodes are evicted as soon as they're no longer in
* use and their master key has been removed.
*
* Return: 1 if fscrypt wants the inode to be evicted now, otherwise 0
*/
int fscrypt_drop_inode(struct inode *inode)
{
const struct fscrypt_info *ci = READ_ONCE(inode->i_crypt_info);
const struct fscrypt_master_key *mk;
/*
* If ci is NULL, then the inode doesn't have an encryption key set up
* so it's irrelevant. If ci_master_key is NULL, then the master key
* was provided via the legacy mechanism of the process-subscribed
* keyrings, so we don't know whether it's been removed or not.
*/
if (!ci || !ci->ci_master_key)
return 0;
mk = ci->ci_master_key->payload.data[0];
/*
* Note: since we aren't holding ->mk_secret_sem, the result here can
* immediately become outdated. But there's no correctness problem with
* unnecessarily evicting. Nor is there a correctness problem with not
* evicting while iput() is racing with the key being removed, since
* then the thread removing the key will either evict the inode itself
* or will correctly detect that it wasn't evicted due to the race.
*/
return !is_master_key_secret_present(&mk->mk_secret);
}
EXPORT_SYMBOL_GPL(fscrypt_drop_inode);

336
fs/crypto/keysetup_v1.c Normal file
View file

@ -0,0 +1,336 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Key setup for v1 encryption policies
*
* Copyright 2015, 2019 Google LLC
*/
/*
* This file implements compatibility functions for the original encryption
* policy version ("v1"), including:
*
* - Deriving per-file keys using the AES-128-ECB based KDF
* (rather than the new method of using HKDF-SHA512)
*
* - Retrieving fscrypt master keys from process-subscribed keyrings
* (rather than the new method of using a filesystem-level keyring)
*
* - Handling policies with the DIRECT_KEY flag set using a master key table
* (rather than the new method of implementing DIRECT_KEY with per-mode keys
* managed alongside the master keys in the filesystem-level keyring)
*/
#include <crypto/algapi.h>
#include <crypto/skcipher.h>
#include <keys/user-type.h>
#include <linux/hashtable.h>
#include <linux/scatterlist.h>
#include "fscrypt_private.h"
/* Table of keys referenced by DIRECT_KEY policies */
static DEFINE_HASHTABLE(fscrypt_direct_keys, 6); /* 6 bits = 64 buckets */
static DEFINE_SPINLOCK(fscrypt_direct_keys_lock);
/*
* v1 key derivation function. This generates the derived key by encrypting the
* master key with AES-128-ECB using the nonce as the AES key. This provides a
* unique derived key with sufficient entropy for each inode. However, it's
* nonstandard, non-extensible, doesn't evenly distribute the entropy from the
* master key, and is trivially reversible: an attacker who compromises a
* derived key can "decrypt" it to get back to the master key, then derive any
* other key. For all new code, use HKDF instead.
*
* The master key must be at least as long as the derived key. If the master
* key is longer, then only the first 'derived_keysize' bytes are used.
*/
static int derive_key_aes(const u8 *master_key,
const u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE],
u8 *derived_key, unsigned int derived_keysize)
{
int res = 0;
struct skcipher_request *req = NULL;
DECLARE_CRYPTO_WAIT(wait);
struct scatterlist src_sg, dst_sg;
struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
if (IS_ERR(tfm)) {
res = PTR_ERR(tfm);
tfm = NULL;
goto out;
}
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
req = skcipher_request_alloc(tfm, GFP_NOFS);
if (!req) {
res = -ENOMEM;
goto out;
}
skcipher_request_set_callback(req,
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &wait);
res = crypto_skcipher_setkey(tfm, nonce, FS_KEY_DERIVATION_NONCE_SIZE);
if (res < 0)
goto out;
sg_init_one(&src_sg, master_key, derived_keysize);
sg_init_one(&dst_sg, derived_key, derived_keysize);
skcipher_request_set_crypt(req, &src_sg, &dst_sg, derived_keysize,
NULL);
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
out:
skcipher_request_free(req);
crypto_free_skcipher(tfm);
return res;
}
/*
* Search the current task's subscribed keyrings for a "logon" key with
* description prefix:descriptor, and if found acquire a read lock on it and
* return a pointer to its validated payload in *payload_ret.
*/
static struct key *
find_and_lock_process_key(const char *prefix,
const u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE],
unsigned int min_keysize,
const struct fscrypt_key **payload_ret)
{
char *description;
struct key *key;
const struct user_key_payload *ukp;
const struct fscrypt_key *payload;
description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
FSCRYPT_KEY_DESCRIPTOR_SIZE, descriptor);
if (!description)
return ERR_PTR(-ENOMEM);
key = request_key(&key_type_logon, description, NULL);
kfree(description);
if (IS_ERR(key))
return key;
down_read(&key->sem);
ukp = user_key_payload_locked(key);
if (!ukp) /* was the key revoked before we acquired its semaphore? */
goto invalid;
payload = (const struct fscrypt_key *)ukp->data;
if (ukp->datalen != sizeof(struct fscrypt_key) ||
payload->size < 1 || payload->size > FSCRYPT_MAX_KEY_SIZE) {
fscrypt_warn(NULL,
"key with description '%s' has invalid payload",
key->description);
goto invalid;
}
if (payload->size < min_keysize) {
fscrypt_warn(NULL,
"key with description '%s' is too short (got %u bytes, need %u+ bytes)",
key->description, payload->size, min_keysize);
goto invalid;
}
*payload_ret = payload;
return key;
invalid:
up_read(&key->sem);
key_put(key);
return ERR_PTR(-ENOKEY);
}
/* Master key referenced by DIRECT_KEY policy */
struct fscrypt_direct_key {
struct hlist_node dk_node;
refcount_t dk_refcount;
const struct fscrypt_mode *dk_mode;
struct crypto_skcipher *dk_ctfm;
u8 dk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
u8 dk_raw[FSCRYPT_MAX_KEY_SIZE];
};
static void free_direct_key(struct fscrypt_direct_key *dk)
{
if (dk) {
crypto_free_skcipher(dk->dk_ctfm);
kzfree(dk);
}
}
void fscrypt_put_direct_key(struct fscrypt_direct_key *dk)
{
if (!refcount_dec_and_lock(&dk->dk_refcount, &fscrypt_direct_keys_lock))
return;
hash_del(&dk->dk_node);
spin_unlock(&fscrypt_direct_keys_lock);
free_direct_key(dk);
}
/*
* Find/insert the given key into the fscrypt_direct_keys table. If found, it
* is returned with elevated refcount, and 'to_insert' is freed if non-NULL. If
* not found, 'to_insert' is inserted and returned if it's non-NULL; otherwise
* NULL is returned.
*/
static struct fscrypt_direct_key *
find_or_insert_direct_key(struct fscrypt_direct_key *to_insert,
const u8 *raw_key, const struct fscrypt_info *ci)
{
unsigned long hash_key;
struct fscrypt_direct_key *dk;
/*
* Careful: to avoid potentially leaking secret key bytes via timing
* information, we must key the hash table by descriptor rather than by
* raw key, and use crypto_memneq() when comparing raw keys.
*/
BUILD_BUG_ON(sizeof(hash_key) > FSCRYPT_KEY_DESCRIPTOR_SIZE);
memcpy(&hash_key, ci->ci_policy.v1.master_key_descriptor,
sizeof(hash_key));
spin_lock(&fscrypt_direct_keys_lock);
hash_for_each_possible(fscrypt_direct_keys, dk, dk_node, hash_key) {
if (memcmp(ci->ci_policy.v1.master_key_descriptor,
dk->dk_descriptor, FSCRYPT_KEY_DESCRIPTOR_SIZE) != 0)
continue;
if (ci->ci_mode != dk->dk_mode)
continue;
if (crypto_memneq(raw_key, dk->dk_raw, ci->ci_mode->keysize))
continue;
/* using existing tfm with same (descriptor, mode, raw_key) */
refcount_inc(&dk->dk_refcount);
spin_unlock(&fscrypt_direct_keys_lock);
free_direct_key(to_insert);
return dk;
}
if (to_insert)
hash_add(fscrypt_direct_keys, &to_insert->dk_node, hash_key);
spin_unlock(&fscrypt_direct_keys_lock);
return to_insert;
}
/* Prepare to encrypt directly using the master key in the given mode */
static struct fscrypt_direct_key *
fscrypt_get_direct_key(const struct fscrypt_info *ci, const u8 *raw_key)
{
struct fscrypt_direct_key *dk;
int err;
/* Is there already a tfm for this key? */
dk = find_or_insert_direct_key(NULL, raw_key, ci);
if (dk)
return dk;
/* Nope, allocate one. */
dk = kzalloc(sizeof(*dk), GFP_NOFS);
if (!dk)
return ERR_PTR(-ENOMEM);
refcount_set(&dk->dk_refcount, 1);
dk->dk_mode = ci->ci_mode;
dk->dk_ctfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key,
ci->ci_inode);
if (IS_ERR(dk->dk_ctfm)) {
err = PTR_ERR(dk->dk_ctfm);
dk->dk_ctfm = NULL;
goto err_free_dk;
}
memcpy(dk->dk_descriptor, ci->ci_policy.v1.master_key_descriptor,
FSCRYPT_KEY_DESCRIPTOR_SIZE);
memcpy(dk->dk_raw, raw_key, ci->ci_mode->keysize);
return find_or_insert_direct_key(dk, raw_key, ci);
err_free_dk:
free_direct_key(dk);
return ERR_PTR(err);
}
/* v1 policy, DIRECT_KEY: use the master key directly */
static int setup_v1_file_key_direct(struct fscrypt_info *ci,
const u8 *raw_master_key)
{
const struct fscrypt_mode *mode = ci->ci_mode;
struct fscrypt_direct_key *dk;
if (!fscrypt_mode_supports_direct_key(mode)) {
fscrypt_warn(ci->ci_inode,
"Direct key mode not allowed with %s",
mode->friendly_name);
return -EINVAL;
}
if (ci->ci_policy.v1.contents_encryption_mode !=
ci->ci_policy.v1.filenames_encryption_mode) {
fscrypt_warn(ci->ci_inode,
"Direct key mode not allowed with different contents and filenames modes");
return -EINVAL;
}
dk = fscrypt_get_direct_key(ci, raw_master_key);
if (IS_ERR(dk))
return PTR_ERR(dk);
ci->ci_direct_key = dk;
ci->ci_ctfm = dk->dk_ctfm;
return 0;
}
/* v1 policy, !DIRECT_KEY: derive the file's encryption key */
static int setup_v1_file_key_derived(struct fscrypt_info *ci,
const u8 *raw_master_key)
{
u8 *derived_key;
int err;
/*
* This cannot be a stack buffer because it will be passed to the
* scatterlist crypto API during derive_key_aes().
*/
derived_key = kmalloc(ci->ci_mode->keysize, GFP_NOFS);
if (!derived_key)
return -ENOMEM;
err = derive_key_aes(raw_master_key, ci->ci_nonce,
derived_key, ci->ci_mode->keysize);
if (err)
goto out;
err = fscrypt_set_derived_key(ci, derived_key);
out:
kzfree(derived_key);
return err;
}
int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, const u8 *raw_master_key)
{
if (ci->ci_policy.v1.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY)
return setup_v1_file_key_direct(ci, raw_master_key);
else
return setup_v1_file_key_derived(ci, raw_master_key);
}
int fscrypt_setup_v1_file_key_via_subscribed_keyrings(struct fscrypt_info *ci)
{
struct key *key;
const struct fscrypt_key *payload;
int err;
key = find_and_lock_process_key(FSCRYPT_KEY_DESC_PREFIX,
ci->ci_policy.v1.master_key_descriptor,
ci->ci_mode->keysize, &payload);
if (key == ERR_PTR(-ENOKEY) && ci->ci_inode->i_sb->s_cop->key_prefix) {
key = find_and_lock_process_key(ci->ci_inode->i_sb->s_cop->key_prefix,
ci->ci_policy.v1.master_key_descriptor,
ci->ci_mode->keysize, &payload);
}
if (IS_ERR(key))
return PTR_ERR(key);
err = fscrypt_setup_v1_file_key(ci, payload->raw);
up_read(&key->sem);
key_put(key);
return err;
}

477
fs/crypto/policy.c
View file

@ -5,8 +5,9 @@
* Copyright (C) 2015, Google, Inc.
* Copyright (C) 2015, Motorola Mobility.
*
* Written by Michael Halcrow, 2015.
* Originally written by Michael Halcrow, 2015.
* Modified by Jaegeuk Kim, 2015.
* Modified by Eric Biggers, 2019 for v2 policy support.
*/
#include <linux/random.h>
@ -14,70 +15,342 @@
#include <linux/mount.h>
#include "fscrypt_private.h"
/*
* check whether an encryption policy is consistent with an encryption context
/**
* fscrypt_policies_equal - check whether two encryption policies are the same
*
* Return: %true if equal, else %false
*/
static bool is_encryption_context_consistent_with_policy(
const struct fscrypt_context *ctx,
const struct fscrypt_policy *policy)
bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
const union fscrypt_policy *policy2)
{
return memcmp(ctx->master_key_descriptor, policy->master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE) == 0 &&
(ctx->flags == policy->flags) &&
(ctx->contents_encryption_mode ==
policy->contents_encryption_mode) &&
(ctx->filenames_encryption_mode ==
policy->filenames_encryption_mode);
if (policy1->version != policy2->version)
return false;
return !memcmp(policy1, policy2, fscrypt_policy_size(policy1));
}
static int create_encryption_context_from_policy(struct inode *inode,
const struct fscrypt_policy *policy)
static bool supported_iv_ino_lblk_64_policy(
const struct fscrypt_policy_v2 *policy,
const struct inode *inode)
{
struct fscrypt_context ctx;
struct super_block *sb = inode->i_sb;
int ino_bits = 64, lblk_bits = 64;
ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE);
if (policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {
fscrypt_warn(inode,
"The DIRECT_KEY and IV_INO_LBLK_64 flags are mutually exclusive");
return false;
}
/*
* It's unsafe to include inode numbers in the IVs if the filesystem can
* potentially renumber inodes, e.g. via filesystem shrinking.
*/
if (!sb->s_cop->has_stable_inodes ||
!sb->s_cop->has_stable_inodes(sb)) {
fscrypt_warn(inode,
"Can't use IV_INO_LBLK_64 policy on filesystem '%s' because it doesn't have stable inode numbers",
sb->s_id);
return false;
}
if (sb->s_cop->get_ino_and_lblk_bits)
sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits);
if (ino_bits > 32 || lblk_bits > 32) {
fscrypt_warn(inode,
"Can't use IV_INO_LBLK_64 policy on filesystem '%s' because it doesn't use 32-bit inode and block numbers",
sb->s_id);
return false;
}
return true;
}
if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
policy->filenames_encryption_mode))
/**
* fscrypt_supported_policy - check whether an encryption policy is supported
*
* Given an encryption policy, check whether all its encryption modes and other
* settings are supported by this kernel. (But we don't currently don't check
* for crypto API support here, so attempting to use an algorithm not configured
* into the crypto API will still fail later.)
*
* Return: %true if supported, else %false
*/
bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
const struct inode *inode)
{
switch (policy_u->version) {
case FSCRYPT_POLICY_V1: {
const struct fscrypt_policy_v1 *policy = &policy_u->v1;
if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
policy->filenames_encryption_mode)) {
fscrypt_warn(inode,
"Unsupported encryption modes (contents %d, filenames %d)",
policy->contents_encryption_mode,
policy->filenames_encryption_mode);
return false;
}
if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
FSCRYPT_POLICY_FLAG_DIRECT_KEY)) {
fscrypt_warn(inode,
"Unsupported encryption flags (0x%02x)",
policy->flags);
return false;
}
return true;
}
case FSCRYPT_POLICY_V2: {
const struct fscrypt_policy_v2 *policy = &policy_u->v2;
if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
policy->filenames_encryption_mode)) {
fscrypt_warn(inode,
"Unsupported encryption modes (contents %d, filenames %d)",
policy->contents_encryption_mode,
policy->filenames_encryption_mode);
return false;
}
if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) {
fscrypt_warn(inode,
"Unsupported encryption flags (0x%02x)",
policy->flags);
return false;
}
if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) &&
!supported_iv_ino_lblk_64_policy(policy, inode))
return false;
if (memchr_inv(policy->__reserved, 0,
sizeof(policy->__reserved))) {
fscrypt_warn(inode,
"Reserved bits set in encryption policy");
return false;
}
return true;
}
}
return false;
}
/**
* fscrypt_new_context_from_policy - create a new fscrypt_context from a policy
*
* Create an fscrypt_context for an inode that is being assigned the given
* encryption policy. A new nonce is randomly generated.
*
* Return: the size of the new context in bytes.
*/
static int fscrypt_new_context_from_policy(union fscrypt_context *ctx_u,
const union fscrypt_policy *policy_u)
{
memset(ctx_u, 0, sizeof(*ctx_u));
switch (policy_u->version) {
case FSCRYPT_POLICY_V1: {
const struct fscrypt_policy_v1 *policy = &policy_u->v1;
struct fscrypt_context_v1 *ctx = &ctx_u->v1;
ctx->version = FSCRYPT_CONTEXT_V1;
ctx->contents_encryption_mode =
policy->contents_encryption_mode;
ctx->filenames_encryption_mode =
policy->filenames_encryption_mode;
ctx->flags = policy->flags;
memcpy(ctx->master_key_descriptor,
policy->master_key_descriptor,
sizeof(ctx->master_key_descriptor));
get_random_bytes(ctx->nonce, sizeof(ctx->nonce));
return sizeof(*ctx);
}
case FSCRYPT_POLICY_V2: {
const struct fscrypt_policy_v2 *policy = &policy_u->v2;
struct fscrypt_context_v2 *ctx = &ctx_u->v2;
ctx->version = FSCRYPT_CONTEXT_V2;
ctx->contents_encryption_mode =
policy->contents_encryption_mode;
ctx->filenames_encryption_mode =
policy->filenames_encryption_mode;
ctx->flags = policy->flags;
memcpy(ctx->master_key_identifier,
policy->master_key_identifier,
sizeof(ctx->master_key_identifier));
get_random_bytes(ctx->nonce, sizeof(ctx->nonce));
return sizeof(*ctx);
}
}
BUG();
}
/**
* fscrypt_policy_from_context - convert an fscrypt_context to an fscrypt_policy
*
* Given an fscrypt_context, build the corresponding fscrypt_policy.
*
* Return: 0 on success, or -EINVAL if the fscrypt_context has an unrecognized
* version number or size.
*
* This does *not* validate the settings within the policy itself, e.g. the
* modes, flags, and reserved bits. Use fscrypt_supported_policy() for that.
*/
int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
const union fscrypt_context *ctx_u,
int ctx_size)
{
memset(policy_u, 0, sizeof(*policy_u));
if (ctx_size <= 0 || ctx_size != fscrypt_context_size(ctx_u))
return -EINVAL;
if (policy->flags & ~FS_POLICY_FLAGS_VALID)
switch (ctx_u->version) {
case FSCRYPT_CONTEXT_V1: {
const struct fscrypt_context_v1 *ctx = &ctx_u->v1;
struct fscrypt_policy_v1 *policy = &policy_u->v1;
policy->version = FSCRYPT_POLICY_V1;
policy->contents_encryption_mode =
ctx->contents_encryption_mode;
policy->filenames_encryption_mode =
ctx->filenames_encryption_mode;
policy->flags = ctx->flags;
memcpy(policy->master_key_descriptor,
ctx->master_key_descriptor,
sizeof(policy->master_key_descriptor));
return 0;
}
case FSCRYPT_CONTEXT_V2: {
const struct fscrypt_context_v2 *ctx = &ctx_u->v2;
struct fscrypt_policy_v2 *policy = &policy_u->v2;
policy->version = FSCRYPT_POLICY_V2;
policy->contents_encryption_mode =
ctx->contents_encryption_mode;
policy->filenames_encryption_mode =
ctx->filenames_encryption_mode;
policy->flags = ctx->flags;
memcpy(policy->__reserved, ctx->__reserved,
sizeof(policy->__reserved));
memcpy(policy->master_key_identifier,
ctx->master_key_identifier,
sizeof(policy->master_key_identifier));
return 0;
}
}
/* unreachable */
return -EINVAL;
}
/* Retrieve an inode's encryption policy */
static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy)
{
const struct fscrypt_info *ci;
union fscrypt_context ctx;
int ret;
ci = READ_ONCE(inode->i_crypt_info);
if (ci) {
/* key available, use the cached policy */
*policy = ci->ci_policy;
return 0;
}
if (!IS_ENCRYPTED(inode))
return -ENODATA;
ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (ret < 0)
return (ret == -ERANGE) ? -EINVAL : ret;
return fscrypt_policy_from_context(policy, &ctx, ret);
}
static int set_encryption_policy(struct inode *inode,
const union fscrypt_policy *policy)
{
union fscrypt_context ctx;
int ctxsize;
int err;
if (!fscrypt_supported_policy(policy, inode))
return -EINVAL;
ctx.contents_encryption_mode = policy->contents_encryption_mode;
ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
ctx.flags = policy->flags;
BUILD_BUG_ON(sizeof(ctx.nonce) != FS_KEY_DERIVATION_NONCE_SIZE);
get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
switch (policy->version) {
case FSCRYPT_POLICY_V1:
/*
* The original encryption policy version provided no way of
* verifying that the correct master key was supplied, which was
* insecure in scenarios where multiple users have access to the
* same encrypted files (even just read-only access). The new
* encryption policy version fixes this and also implies use of
* an improved key derivation function and allows non-root users
* to securely remove keys. So as long as compatibility with
* old kernels isn't required, it is recommended to use the new
* policy version for all new encrypted directories.
*/
pr_warn_once("%s (pid %d) is setting deprecated v1 encryption policy; recommend upgrading to v2.\n",
current->comm, current->pid);
break;
case FSCRYPT_POLICY_V2:
err = fscrypt_verify_key_added(inode->i_sb,
policy->v2.master_key_identifier);
if (err)
return err;
break;
default:
WARN_ON(1);
return -EINVAL;
}
return inode->i_sb->s_cop->set_context(inode, &ctx, sizeof(ctx), NULL);
ctxsize = fscrypt_new_context_from_policy(&ctx, policy);
return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, NULL);
}
int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
{
struct fscrypt_policy policy;
union fscrypt_policy policy;
union fscrypt_policy existing_policy;
struct inode *inode = file_inode(filp);
u8 version;
int size;
int ret;
struct fscrypt_context ctx;
if (copy_from_user(&policy, arg, sizeof(policy)))
if (get_user(policy.version, (const u8 __user *)arg))
return -EFAULT;
size = fscrypt_policy_size(&policy);
if (size <= 0)
return -EINVAL;
/*
* We should just copy the remaining 'size - 1' bytes here, but a
* bizarre bug in gcc 7 and earlier (fixed by gcc r255731) causes gcc to
* think that size can be 0 here (despite the check above!) *and* that
* it's a compile-time constant. Thus it would think copy_from_user()
* is passed compile-time constant ULONG_MAX, causing the compile-time
* buffer overflow check to fail, breaking the build. This only occurred
* when building an i386 kernel with -Os and branch profiling enabled.
*
* Work around it by just copying the first byte again...
*/
version = policy.version;
if (copy_from_user(&policy, arg, size))
return -EFAULT;
policy.version = version;
if (!inode_owner_or_capable(inode))
return -EACCES;
if (policy.version != 0)
return -EINVAL;
ret = mnt_want_write_file(filp);
if (ret)
return ret;
inode_lock(inode);
ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
ret = fscrypt_get_policy(inode, &existing_policy);
if (ret == -ENODATA) {
if (!S_ISDIR(inode->i_mode))
ret = -ENOTDIR;
@ -86,14 +359,10 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
else if (!inode->i_sb->s_cop->empty_dir(inode))
ret = -ENOTEMPTY;
else
ret = create_encryption_context_from_policy(inode,
&policy);
} else if (ret == sizeof(ctx) &&
is_encryption_context_consistent_with_policy(&ctx,
&policy)) {
/* The file already uses the same encryption policy. */
ret = 0;
} else if (ret >= 0 || ret == -ERANGE) {
ret = set_encryption_policy(inode, &policy);
} else if (ret == -EINVAL ||
(ret == 0 && !fscrypt_policies_equal(&policy,
&existing_policy))) {
/* The file already uses a different encryption policy. */
ret = -EEXIST;
}
@ -105,37 +374,57 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
}
EXPORT_SYMBOL(fscrypt_ioctl_set_policy);
/* Original ioctl version; can only get the original policy version */
int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
{
struct inode *inode = file_inode(filp);
struct fscrypt_context ctx;
struct fscrypt_policy policy;
int res;
union fscrypt_policy policy;
int err;
if (!IS_ENCRYPTED(inode))
return -ENODATA;
err = fscrypt_get_policy(file_inode(filp), &policy);
if (err)
return err;
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res < 0 && res != -ERANGE)
return res;
if (res != sizeof(ctx))
return -EINVAL;
if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
if (policy.version != FSCRYPT_POLICY_V1)
return -EINVAL;
policy.version = 0;
policy.contents_encryption_mode = ctx.contents_encryption_mode;
policy.filenames_encryption_mode = ctx.filenames_encryption_mode;
policy.flags = ctx.flags;
memcpy(policy.master_key_descriptor, ctx.master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE);
if (copy_to_user(arg, &policy, sizeof(policy)))
if (copy_to_user(arg, &policy, sizeof(policy.v1)))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(fscrypt_ioctl_get_policy);
/* Extended ioctl version; can get policies of any version */
int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *uarg)
{
struct fscrypt_get_policy_ex_arg arg;
union fscrypt_policy *policy = (union fscrypt_policy *)&arg.policy;
size_t policy_size;
int err;
/* arg is policy_size, then policy */
BUILD_BUG_ON(offsetof(typeof(arg), policy_size) != 0);
BUILD_BUG_ON(offsetofend(typeof(arg), policy_size) !=
offsetof(typeof(arg), policy));
BUILD_BUG_ON(sizeof(arg.policy) != sizeof(*policy));
err = fscrypt_get_policy(file_inode(filp), policy);
if (err)
return err;
policy_size = fscrypt_policy_size(policy);
if (copy_from_user(&arg, uarg, sizeof(arg.policy_size)))
return -EFAULT;
if (policy_size > arg.policy_size)
return -EOVERFLOW;
arg.policy_size = policy_size;
if (copy_to_user(uarg, &arg, sizeof(arg.policy_size) + policy_size))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_policy_ex);
/**
* fscrypt_has_permitted_context() - is a file's encryption policy permitted
* within its directory?
@ -157,10 +446,8 @@ EXPORT_SYMBOL(fscrypt_ioctl_get_policy);
*/
int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
{
const struct fscrypt_operations *cops = parent->i_sb->s_cop;
const struct fscrypt_info *parent_ci, *child_ci;
struct fscrypt_context parent_ctx, child_ctx;
int res;
union fscrypt_policy parent_policy, child_policy;
int err;
/* No restrictions on file types which are never encrypted */
if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) &&
@ -190,41 +477,22 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
* In any case, if an unexpected error occurs, fall back to "forbidden".
*/
res = fscrypt_get_encryption_info(parent);
if (res)
err = fscrypt_get_encryption_info(parent);
if (err)
return 0;
res = fscrypt_get_encryption_info(child);
if (res)
return 0;
parent_ci = READ_ONCE(parent->i_crypt_info);
child_ci = READ_ONCE(child->i_crypt_info);
if (parent_ci && child_ci) {
return memcmp(parent_ci->ci_master_key_descriptor,
child_ci->ci_master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE) == 0 &&
(parent_ci->ci_data_mode == child_ci->ci_data_mode) &&
(parent_ci->ci_filename_mode ==
child_ci->ci_filename_mode) &&
(parent_ci->ci_flags == child_ci->ci_flags);
}
res = cops->get_context(parent, &parent_ctx, sizeof(parent_ctx));
if (res != sizeof(parent_ctx))
err = fscrypt_get_encryption_info(child);
if (err)
return 0;
res = cops->get_context(child, &child_ctx, sizeof(child_ctx));
if (res != sizeof(child_ctx))
err = fscrypt_get_policy(parent, &parent_policy);
if (err)
return 0;
return memcmp(parent_ctx.master_key_descriptor,
child_ctx.master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE) == 0 &&
(parent_ctx.contents_encryption_mode ==
child_ctx.contents_encryption_mode) &&
(parent_ctx.filenames_encryption_mode ==
child_ctx.filenames_encryption_mode) &&
(parent_ctx.flags == child_ctx.flags);
err = fscrypt_get_policy(child, &child_policy);
if (err)
return 0;
return fscrypt_policies_equal(&parent_policy, &child_policy);
}
EXPORT_SYMBOL(fscrypt_has_permitted_context);
@ -240,7 +508,8 @@ EXPORT_SYMBOL(fscrypt_has_permitted_context);
int fscrypt_inherit_context(struct inode *parent, struct inode *child,
void *fs_data, bool preload)
{
struct fscrypt_context ctx;
union fscrypt_context ctx;
int ctxsize;
struct fscrypt_info *ci;
int res;
@ -252,16 +521,10 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child,
if (ci == NULL)
return -ENOKEY;
ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
ctx.contents_encryption_mode = ci->ci_data_mode;
ctx.filenames_encryption_mode = ci->ci_filename_mode;
ctx.flags = ci->ci_flags;
memcpy(ctx.master_key_descriptor, ci->ci_master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE);
get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
ctxsize = fscrypt_new_context_from_policy(&ctx, &ci->ci_policy);
BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE);
res = parent->i_sb->s_cop->set_context(child, &ctx,
sizeof(ctx), fs_data);
res = parent->i_sb->s_cop->set_context(child, &ctx, ctxsize, fs_data);
if (res)
return res;
return preload ? fscrypt_get_encryption_info(child): 0;

3
fs/ext4/ext4.h
View file

@ -1140,6 +1140,7 @@ struct ext4_inode_info {
#define EXT4_MOUNT_JOURNAL_CHECKSUM 0x800000 /* Journal checksums */
#define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT 0x1000000 /* Journal Async Commit */
#define EXT4_MOUNT_WARN_ON_ERROR 0x2000000 /* Trigger WARN_ON on error */
#define EXT4_MOUNT_INLINECRYPT 0x4000000 /* Inline encryption support */
#define EXT4_MOUNT_DELALLOC 0x8000000 /* Delalloc support */
#define EXT4_MOUNT_DATA_ERR_ABORT 0x10000000 /* Abort on file data write */
#define EXT4_MOUNT_BLOCK_VALIDITY 0x20000000 /* Block validity checking */
@ -1666,6 +1667,7 @@ static inline bool ext4_verity_in_progress(struct inode *inode)
#define EXT4_FEATURE_COMPAT_RESIZE_INODE 0x0010
#define EXT4_FEATURE_COMPAT_DIR_INDEX 0x0020
#define EXT4_FEATURE_COMPAT_SPARSE_SUPER2 0x0200
#define EXT4_FEATURE_COMPAT_STABLE_INODES 0x0800
#define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT4_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
@ -1767,6 +1769,7 @@ EXT4_FEATURE_COMPAT_FUNCS(xattr, EXT_ATTR)
EXT4_FEATURE_COMPAT_FUNCS(resize_inode, RESIZE_INODE)
EXT4_FEATURE_COMPAT_FUNCS(dir_index, DIR_INDEX)
EXT4_FEATURE_COMPAT_FUNCS(sparse_super2, SPARSE_SUPER2)
EXT4_FEATURE_COMPAT_FUNCS(stable_inodes, STABLE_INODES)
EXT4_FEATURE_RO_COMPAT_FUNCS(sparse_super, SPARSE_SUPER)
EXT4_FEATURE_RO_COMPAT_FUNCS(large_file, LARGE_FILE)

6
fs/ext4/inode.c
View file

@ -1237,8 +1237,7 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
(block_start < from || block_end > to)) {
ll_rw_block(REQ_OP_READ, 0, 1, &bh);
*wait_bh++ = bh;
decrypt = IS_ENCRYPTED(inode) &&
S_ISREG(inode->i_mode);
decrypt = fscrypt_inode_uses_fs_layer_crypto(inode);
}
}
/*
@ -4137,8 +4136,7 @@ static int __ext4_block_zero_page_range(handle_t *handle,
/* Uhhuh. Read error. Complain and punt. */
if (!buffer_uptodate(bh))
goto unlock;
if (S_ISREG(inode->i_mode) &&
IS_ENCRYPTED(inode)) {
if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
/* We expect the key to be set. */
BUG_ON(!fscrypt_has_encryption_key(inode));
BUG_ON(blocksize != PAGE_SIZE);

32
fs/ext4/ioctl.c
View file

@ -1131,8 +1131,35 @@ resizefs_out:
#endif
}
case EXT4_IOC_GET_ENCRYPTION_POLICY:
if (!ext4_has_feature_encrypt(sb))
return -EOPNOTSUPP;
return fscrypt_ioctl_get_policy(filp, (void __user *)arg);
case FS_IOC_GET_ENCRYPTION_POLICY_EX:
if (!ext4_has_feature_encrypt(sb))
return -EOPNOTSUPP;
return fscrypt_ioctl_get_policy_ex(filp, (void __user *)arg);
case FS_IOC_ADD_ENCRYPTION_KEY:
if (!ext4_has_feature_encrypt(sb))
return -EOPNOTSUPP;
return fscrypt_ioctl_add_key(filp, (void __user *)arg);
case FS_IOC_REMOVE_ENCRYPTION_KEY:
if (!ext4_has_feature_encrypt(sb))
return -EOPNOTSUPP;
return fscrypt_ioctl_remove_key(filp, (void __user *)arg);
case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
if (!ext4_has_feature_encrypt(sb))
return -EOPNOTSUPP;
return fscrypt_ioctl_remove_key_all_users(filp,
(void __user *)arg);
case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
if (!ext4_has_feature_encrypt(sb))
return -EOPNOTSUPP;
return fscrypt_ioctl_get_key_status(filp, (void __user *)arg);
case EXT4_IOC_FSGETXATTR:
{
struct fsxattr fa;
@ -1265,6 +1292,11 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case EXT4_IOC_SET_ENCRYPTION_POLICY:
case EXT4_IOC_GET_ENCRYPTION_PWSALT:
case EXT4_IOC_GET_ENCRYPTION_POLICY:
case FS_IOC_GET_ENCRYPTION_POLICY_EX:
case FS_IOC_ADD_ENCRYPTION_KEY:
case FS_IOC_REMOVE_ENCRYPTION_KEY:
case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
case EXT4_IOC_SHUTDOWN:
case FS_IOC_GETFSMAP:
case FS_IOC_ENABLE_VERITY:

11
fs/ext4/page-io.c
View file

@ -362,10 +362,16 @@ static int io_submit_init_bio(struct ext4_io_submit *io,
struct buffer_head *bh)
{
struct bio *bio;
int err;
bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
if (!bio)
return -ENOMEM;
err = fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO);
if (err) {
bio_put(bio);
return err;
}
wbc_init_bio(io->io_wbc, bio);
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bio_set_dev(bio, bh->b_bdev);
@ -383,7 +389,8 @@ static int io_submit_add_bh(struct ext4_io_submit *io,
{
int ret;
if (io->io_bio && bh->b_blocknr != io->io_next_block) {
if (io->io_bio && (bh->b_blocknr != io->io_next_block ||
!fscrypt_mergeable_bio_bh(io->io_bio, bh))) {
submit_and_retry:
ext4_io_submit(io);
}
@ -469,7 +476,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
bh = head = page_buffers(page);
if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) && nr_to_submit) {
if (fscrypt_inode_uses_fs_layer_crypto(inode) && nr_to_submit) {
gfp_t gfp_flags = GFP_NOFS;
retry_encrypt:

15
fs/ext4/readpage.c
View file

@ -198,7 +198,7 @@ static struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode,
unsigned int post_read_steps = 0;
struct bio_post_read_ctx *ctx = NULL;
if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
if (fscrypt_inode_uses_fs_layer_crypto(inode))
post_read_steps |= 1 << STEP_DECRYPT;
if (ext4_need_verity(inode, first_idx))
@ -259,6 +259,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
const unsigned blkbits = inode->i_blkbits;
const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
const unsigned blocksize = 1 << blkbits;
sector_t next_block;
sector_t block_in_file;
sector_t last_block;
sector_t last_block_in_file;
@ -290,7 +291,8 @@ int ext4_mpage_readpages(struct address_space *mapping,
if (page_has_buffers(page))
goto confused;
block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits);
block_in_file = next_block =
(sector_t)page->index << (PAGE_SHIFT - blkbits);
last_block = block_in_file + nr_pages * blocks_per_page;
last_block_in_file = (ext4_readpage_limit(inode) +
blocksize - 1) >> blkbits;
@ -390,7 +392,8 @@ int ext4_mpage_readpages(struct address_space *mapping,
* This page will go to BIO. Do we need to send this
* BIO off first?
*/
if (bio && (last_block_in_bio != blocks[0] - 1)) {
if (bio && (last_block_in_bio != blocks[0] - 1 ||
!fscrypt_mergeable_bio(bio, inode, next_block))) {
submit_and_realloc:
ext4_submit_bio_read(bio);
bio = NULL;
@ -402,6 +405,12 @@ int ext4_mpage_readpages(struct address_space *mapping,
min_t(int, nr_pages, BIO_MAX_PAGES));
if (!bio)
goto set_error_page;
if (fscrypt_set_bio_crypt_ctx(bio, inode, next_block,
GFP_KERNEL) != 0) {
bio_put(bio);
bio = NULL;
goto set_error_page;
}
ctx = get_bio_post_read_ctx(inode, bio, page->index);
if (IS_ERR(ctx)) {
bio_put(bio);

30
fs/ext4/super.c
View file

@ -1107,6 +1107,9 @@ static int ext4_drop_inode(struct inode *inode)
{
int drop = generic_drop_inode(inode);
if (!drop)
drop = fscrypt_drop_inode(inode);
trace_ext4_drop_inode(inode, drop);
return drop;
}
@ -1346,6 +1349,23 @@ static bool ext4_dummy_context(struct inode *inode)
return DUMMY_ENCRYPTION_ENABLED(EXT4_SB(inode->i_sb));
}
static bool ext4_has_stable_inodes(struct super_block *sb)
{
return ext4_has_feature_stable_inodes(sb);
}
static void ext4_get_ino_and_lblk_bits(struct super_block *sb,
int *ino_bits_ret, int *lblk_bits_ret)
{
*ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count);
*lblk_bits_ret = 8 * sizeof(ext4_lblk_t);
}
static bool ext4_inline_crypt_enabled(struct super_block *sb)
{
return test_opt(sb, INLINECRYPT);
}
static const struct fscrypt_operations ext4_cryptops = {
.key_prefix = "ext4:",
.get_context = ext4_get_context,
@ -1353,6 +1373,9 @@ static const struct fscrypt_operations ext4_cryptops = {
.dummy_context = ext4_dummy_context,
.empty_dir = ext4_empty_dir,
.max_namelen = EXT4_NAME_LEN,
.has_stable_inodes = ext4_has_stable_inodes,
.get_ino_and_lblk_bits = ext4_get_ino_and_lblk_bits,
.inline_crypt_enabled = ext4_inline_crypt_enabled,
};
#endif
@ -1447,6 +1470,7 @@ enum {
Opt_journal_path, Opt_journal_checksum, Opt_journal_async_commit,
Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
Opt_data_err_abort, Opt_data_err_ignore, Opt_test_dummy_encryption,
Opt_inlinecrypt,
Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
@ -1543,6 +1567,7 @@ static const match_table_t tokens = {
{Opt_noinit_itable, "noinit_itable"},
{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
{Opt_test_dummy_encryption, "test_dummy_encryption"},
{Opt_inlinecrypt, "inlinecrypt"},
{Opt_nombcache, "nombcache"},
{Opt_nombcache, "no_mbcache"}, /* for backward compatibility */
{Opt_removed, "check=none"}, /* mount option from ext2/3 */
@ -1754,6 +1779,11 @@ static const struct mount_opts {
{Opt_jqfmt_vfsv1, QFMT_VFS_V1, MOPT_QFMT},
{Opt_max_dir_size_kb, 0, MOPT_GTE0},
{Opt_test_dummy_encryption, 0, MOPT_GTE0},
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
{Opt_inlinecrypt, EXT4_MOUNT_INLINECRYPT, MOPT_SET},
#else
{Opt_inlinecrypt, EXT4_MOUNT_INLINECRYPT, MOPT_NOSUPPORT},
#endif
{Opt_nombcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
{Opt_err, 0, 0}
};

77
fs/f2fs/data.c
View file

@ -317,6 +317,35 @@ static struct bio *__bio_alloc(struct f2fs_io_info *fio, int npages)
return bio;
}
static int f2fs_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode,
pgoff_t first_idx,
const struct f2fs_io_info *fio,
gfp_t gfp_mask)
{
/*
* The f2fs garbage collector sets ->encrypted_page when it wants to
* read/write raw data without encryption.
*/
if (fio && fio->encrypted_page)
return 0;
return fscrypt_set_bio_crypt_ctx(bio, inode, first_idx, gfp_mask);
}
static bool f2fs_crypt_mergeable_bio(struct bio *bio, const struct inode *inode,
pgoff_t next_idx,
const struct f2fs_io_info *fio)
{
/*
* The f2fs garbage collector sets ->encrypted_page when it wants to
* read/write raw data without encryption.
*/
if (fio && fio->encrypted_page)
return !bio_has_crypt_ctx(bio);
return fscrypt_mergeable_bio(bio, inode, next_idx);
}
static inline void __submit_bio(struct f2fs_sb_info *sbi,
struct bio *bio, enum page_type type)
{
@ -514,6 +543,7 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
struct bio *bio;
struct page *page = fio->encrypted_page ?
fio->encrypted_page : fio->page;
int err;
if (!f2fs_is_valid_blkaddr(fio->sbi, fio->new_blkaddr,
fio->is_por ? META_POR : (__is_meta_io(fio) ?
@ -526,6 +556,13 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
/* Allocate a new bio */
bio = __bio_alloc(fio, 1);
err = f2fs_set_bio_crypt_ctx(bio, fio->page->mapping->host,
fio->page->index, fio, GFP_NOIO);
if (err) {
bio_put(bio);
return err;
}
if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
bio_put(bio);
return -EFAULT;
@ -716,13 +753,18 @@ int f2fs_merge_page_bio(struct f2fs_io_info *fio)
trace_f2fs_submit_page_bio(page, fio);
f2fs_trace_ios(fio, 0);
if (bio && !page_is_mergeable(fio->sbi, bio, *fio->last_block,
fio->new_blkaddr))
if (bio && (!page_is_mergeable(fio->sbi, bio, *fio->last_block,
fio->new_blkaddr) ||
!f2fs_crypt_mergeable_bio(bio, fio->page->mapping->host,
fio->page->index, fio)))
f2fs_submit_merged_ipu_write(fio->sbi, &bio, NULL);
alloc_new:
if (!bio) {
bio = __bio_alloc(fio, BIO_MAX_PAGES);
f2fs_set_bio_crypt_ctx(bio, fio->page->mapping->host,
fio->page->index, fio,
GFP_NOIO | __GFP_NOFAIL);
bio_set_op_attrs(bio, fio->op, fio->op_flags);
add_bio_entry(fio->sbi, bio, page, fio->temp);
@ -774,8 +816,11 @@ next:
inc_page_count(sbi, WB_DATA_TYPE(bio_page));
if (io->bio && !io_is_mergeable(sbi, io->bio, io, fio,
io->last_block_in_bio, fio->new_blkaddr))
if (io->bio &&
(!io_is_mergeable(sbi, io->bio, io, fio, io->last_block_in_bio,
fio->new_blkaddr) ||
!f2fs_crypt_mergeable_bio(io->bio, fio->page->mapping->host,
fio->page->index, fio)))
__submit_merged_bio(io);
alloc_new:
if (io->bio == NULL) {
@ -787,7 +832,9 @@ alloc_new:
goto skip;
}
io->bio = __bio_alloc(fio, BIO_MAX_PAGES);
f2fs_set_bio_crypt_ctx(io->bio, fio->page->mapping->host,
fio->page->index, fio,
GFP_NOIO | __GFP_NOFAIL);
io->fio = *fio;
}
@ -827,15 +874,23 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
struct bio *bio;
struct bio_post_read_ctx *ctx;
unsigned int post_read_steps = 0;
int err;
bio = f2fs_bio_alloc(sbi, min_t(int, nr_pages, BIO_MAX_PAGES), false);
if (!bio)
return ERR_PTR(-ENOMEM);
err = f2fs_set_bio_crypt_ctx(bio, inode, first_idx, NULL, GFP_NOFS);
if (err) {
bio_put(bio);
return ERR_PTR(err);
}
f2fs_target_device(sbi, blkaddr, bio);
bio->bi_end_io = f2fs_read_end_io;
bio_set_op_attrs(bio, REQ_OP_READ, op_flag);
if (f2fs_encrypted_file(inode))
if (fscrypt_inode_uses_fs_layer_crypto(inode))
post_read_steps |= 1 << STEP_DECRYPT;
if (f2fs_need_verity(inode, first_idx))
@ -1870,8 +1925,9 @@ zero_out:
* This page will go to BIO. Do we need to send this
* BIO off first?
*/
if (bio && !page_is_mergeable(F2FS_I_SB(inode), bio,
*last_block_in_bio, block_nr)) {
if (bio && (!page_is_mergeable(F2FS_I_SB(inode), bio,
*last_block_in_bio, block_nr) ||
!f2fs_crypt_mergeable_bio(bio, inode, page->index, NULL))) {
submit_and_realloc:
__f2fs_submit_read_bio(F2FS_I_SB(inode), bio, DATA);
bio = NULL;
@ -2013,6 +2069,9 @@ static int encrypt_one_page(struct f2fs_io_info *fio)
/* wait for GCed page writeback via META_MAPPING */
f2fs_wait_on_block_writeback(inode, fio->old_blkaddr);
if (fscrypt_inode_uses_inline_crypto(inode))
return 0;
retry_encrypt:
fio->encrypted_page = fscrypt_encrypt_pagecache_blocks(fio->page,
@ -2188,7 +2247,7 @@ got_it:
f2fs_unlock_op(fio->sbi);
err = f2fs_inplace_write_data(fio);
if (err) {
if (f2fs_encrypted_file(inode))
if (fscrypt_inode_uses_fs_layer_crypto(inode))
fscrypt_finalize_bounce_page(&fio->encrypted_page);
if (PageWriteback(page))
end_page_writeback(page);

3
fs/f2fs/f2fs.h
View file

@ -137,6 +137,9 @@ struct f2fs_mount_info {
int alloc_mode; /* segment allocation policy */
int fsync_mode; /* fsync policy */
bool test_dummy_encryption; /* test dummy encryption */
#ifdef CONFIG_FS_ENCRYPTION
bool inlinecrypt; /* inline encryption enabled */
#endif
block_t unusable_cap; /* Amount of space allowed to be
* unusable when disabling checkpoint
*/

58
fs/f2fs/file.c
View file

@ -2267,6 +2267,49 @@ out_err:
return err;
}
static int f2fs_ioc_get_encryption_policy_ex(struct file *filp,
unsigned long arg)
{
if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
return -EOPNOTSUPP;
return fscrypt_ioctl_get_policy_ex(filp, (void __user *)arg);
}
static int f2fs_ioc_add_encryption_key(struct file *filp, unsigned long arg)
{
if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
return -EOPNOTSUPP;
return fscrypt_ioctl_add_key(filp, (void __user *)arg);
}
static int f2fs_ioc_remove_encryption_key(struct file *filp, unsigned long arg)
{
if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
return -EOPNOTSUPP;
return fscrypt_ioctl_remove_key(filp, (void __user *)arg);
}
static int f2fs_ioc_remove_encryption_key_all_users(struct file *filp,
unsigned long arg)
{
if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
return -EOPNOTSUPP;
return fscrypt_ioctl_remove_key_all_users(filp, (void __user *)arg);
}
static int f2fs_ioc_get_encryption_key_status(struct file *filp,
unsigned long arg)
{
if (!f2fs_sb_has_encrypt(F2FS_I_SB(file_inode(filp))))
return -EOPNOTSUPP;
return fscrypt_ioctl_get_key_status(filp, (void __user *)arg);
}
static int f2fs_ioc_gc(struct file *filp, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@ -3265,6 +3308,16 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return f2fs_ioc_get_encryption_policy(filp, arg);
case F2FS_IOC_GET_ENCRYPTION_PWSALT:
return f2fs_ioc_get_encryption_pwsalt(filp, arg);
case FS_IOC_GET_ENCRYPTION_POLICY_EX:
return f2fs_ioc_get_encryption_policy_ex(filp, arg);
case FS_IOC_ADD_ENCRYPTION_KEY:
return f2fs_ioc_add_encryption_key(filp, arg);
case FS_IOC_REMOVE_ENCRYPTION_KEY:
return f2fs_ioc_remove_encryption_key(filp, arg);
case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
return f2fs_ioc_remove_encryption_key_all_users(filp, arg);
case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
return f2fs_ioc_get_encryption_key_status(filp, arg);
case F2FS_IOC_GARBAGE_COLLECT:
return f2fs_ioc_gc(filp, arg);
case F2FS_IOC_GARBAGE_COLLECT_RANGE:
@ -3396,6 +3449,11 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case F2FS_IOC_SET_ENCRYPTION_POLICY:
case F2FS_IOC_GET_ENCRYPTION_PWSALT:
case F2FS_IOC_GET_ENCRYPTION_POLICY:
case FS_IOC_GET_ENCRYPTION_POLICY_EX:
case FS_IOC_ADD_ENCRYPTION_KEY:
case FS_IOC_REMOVE_ENCRYPTION_KEY:
case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
case F2FS_IOC_GARBAGE_COLLECT:
case F2FS_IOC_GARBAGE_COLLECT_RANGE:
case F2FS_IOC_WRITE_CHECKPOINT:

48
fs/f2fs/super.c
View file

@ -137,6 +137,7 @@ enum {
Opt_alloc,
Opt_fsync,
Opt_test_dummy_encryption,
Opt_inlinecrypt,
Opt_checkpoint_disable,
Opt_checkpoint_disable_cap,
Opt_checkpoint_disable_cap_perc,
@ -199,6 +200,7 @@ static match_table_t f2fs_tokens = {
{Opt_alloc, "alloc_mode=%s"},
{Opt_fsync, "fsync_mode=%s"},
{Opt_test_dummy_encryption, "test_dummy_encryption"},
{Opt_inlinecrypt, "inlinecrypt"},
{Opt_checkpoint_disable, "checkpoint=disable"},
{Opt_checkpoint_disable_cap, "checkpoint=disable:%u"},
{Opt_checkpoint_disable_cap_perc, "checkpoint=disable:%u%%"},
@ -783,6 +785,13 @@ static int parse_options(struct super_block *sb, char *options)
f2fs_info(sbi, "Test dummy encryption mode enabled");
#else
f2fs_info(sbi, "Test dummy encryption mount option ignored");
#endif
break;
case Opt_inlinecrypt:
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
F2FS_OPTION(sbi).inlinecrypt = true;
#else
f2fs_info(sbi, "inline encryption not supported");
#endif
break;
case Opt_checkpoint_disable_cap_perc:
@ -965,6 +974,8 @@ static int f2fs_drop_inode(struct inode *inode)
return 0;
}
ret = generic_drop_inode(inode);
if (!ret)
ret = fscrypt_drop_inode(inode);
trace_f2fs_drop_inode(inode, ret);
return ret;
}
@ -1452,6 +1463,8 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
#ifdef CONFIG_FS_ENCRYPTION
if (F2FS_OPTION(sbi).test_dummy_encryption)
seq_puts(seq, ",test_dummy_encryption");
if (F2FS_OPTION(sbi).inlinecrypt)
seq_puts(seq, ",inlinecrypt");
#endif
if (F2FS_OPTION(sbi).alloc_mode == ALLOC_MODE_DEFAULT)
@ -1480,6 +1493,9 @@ static void default_options(struct f2fs_sb_info *sbi)
F2FS_OPTION(sbi).alloc_mode = ALLOC_MODE_DEFAULT;
F2FS_OPTION(sbi).fsync_mode = FSYNC_MODE_POSIX;
F2FS_OPTION(sbi).test_dummy_encryption = false;
#ifdef CONFIG_FS_ENCRYPTION
F2FS_OPTION(sbi).inlinecrypt = false;
#endif
F2FS_OPTION(sbi).s_resuid = make_kuid(&init_user_ns, F2FS_DEF_RESUID);
F2FS_OPTION(sbi).s_resgid = make_kgid(&init_user_ns, F2FS_DEF_RESGID);
@ -2322,13 +2338,33 @@ static bool f2fs_dummy_context(struct inode *inode)
return DUMMY_ENCRYPTION_ENABLED(F2FS_I_SB(inode));
}
static bool f2fs_has_stable_inodes(struct super_block *sb)
{
return true;
}
static void f2fs_get_ino_and_lblk_bits(struct super_block *sb,
int *ino_bits_ret, int *lblk_bits_ret)
{
*ino_bits_ret = 8 * sizeof(nid_t);
*lblk_bits_ret = 8 * sizeof(block_t);
}
static bool f2fs_inline_crypt_enabled(struct super_block *sb)
{
return F2FS_OPTION(F2FS_SB(sb)).inlinecrypt;
}
static const struct fscrypt_operations f2fs_cryptops = {
.key_prefix = "f2fs:",
.get_context = f2fs_get_context,
.set_context = f2fs_set_context,
.dummy_context = f2fs_dummy_context,
.empty_dir = f2fs_empty_dir,
.max_namelen = F2FS_NAME_LEN,
.key_prefix = "f2fs:",
.get_context = f2fs_get_context,
.set_context = f2fs_set_context,
.dummy_context = f2fs_dummy_context,
.empty_dir = f2fs_empty_dir,
.max_namelen = F2FS_NAME_LEN,
.has_stable_inodes = f2fs_has_stable_inodes,
.get_ino_and_lblk_bits = f2fs_get_ino_and_lblk_bits,
.inline_crypt_enabled = f2fs_inline_crypt_enabled,
};
#endif

7
fs/sdcardfs/main.c
View file

@ -19,6 +19,7 @@
*/
#include "sdcardfs.h"
#include <linux/fscrypt.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/parser.h>
@ -375,6 +376,9 @@ static int sdcardfs_read_super(struct vfsmount *mnt, struct super_block *sb,
list_add(&sb_info->list, &sdcardfs_super_list);
mutex_unlock(&sdcardfs_super_list_lock);
sb_info->fscrypt_nb.notifier_call = sdcardfs_on_fscrypt_key_removed;
fscrypt_register_key_removal_notifier(&sb_info->fscrypt_nb);
if (!silent)
pr_info("sdcardfs: mounted on top of %s type %s\n",
dev_name, lower_sb->s_type->name);
@ -445,6 +449,9 @@ void sdcardfs_kill_sb(struct super_block *sb)
if (sb->s_magic == SDCARDFS_SUPER_MAGIC && sb->s_fs_info) {
sbi = SDCARDFS_SB(sb);
fscrypt_unregister_key_removal_notifier(&sbi->fscrypt_nb);
mutex_lock(&sdcardfs_super_list_lock);
list_del(&sbi->list);
mutex_unlock(&sdcardfs_super_list_lock);

3
fs/sdcardfs/sdcardfs.h
View file

@ -151,6 +151,8 @@ extern struct inode *sdcardfs_iget(struct super_block *sb,
struct inode *lower_inode, userid_t id);
extern int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
struct path *lower_path, userid_t id);
extern int sdcardfs_on_fscrypt_key_removed(struct notifier_block *nb,
unsigned long action, void *data);
/* file private data */
struct sdcardfs_file_info {
@ -224,6 +226,7 @@ struct sdcardfs_sb_info {
struct path obbpath;
void *pkgl_id;
struct list_head list;
struct notifier_block fscrypt_nb;
};
/*

17
fs/sdcardfs/super.c
View file

@ -319,6 +319,23 @@ static int sdcardfs_show_options(struct vfsmount *mnt, struct seq_file *m,
return 0;
};
int sdcardfs_on_fscrypt_key_removed(struct notifier_block *nb,
unsigned long action, void *data)
{
struct sdcardfs_sb_info *sbi = container_of(nb, struct sdcardfs_sb_info,
fscrypt_nb);
/*
* Evict any unused sdcardfs dentries (and hence any unused sdcardfs
* inodes, since sdcardfs doesn't cache unpinned inodes by themselves)
* so that the lower filesystem's encrypted inodes can be evicted.
* This is needed to make the FS_IOC_REMOVE_ENCRYPTION_KEY ioctl
* properly "lock" the files underneath the sdcardfs mount.
*/
shrink_dcache_sb(sbi->sb);
return NOTIFY_OK;
}
const struct super_operations sdcardfs_sops = {
.put_super = sdcardfs_put_super,
.statfs = sdcardfs_statfs,

2
fs/super.c
View file

@ -32,6 +32,7 @@
#include <linux/backing-dev.h>
#include <linux/rculist_bl.h>
#include <linux/cleancache.h>
#include <linux/fscrypt.h>
#include <linux/fsnotify.h>
#include <linux/lockdep.h>
#include <linux/user_namespace.h>
@ -288,6 +289,7 @@ static void __put_super(struct super_block *s)
WARN_ON(s->s_inode_lru.node);
WARN_ON(!list_empty(&s->s_mounts));
security_sb_free(s);
fscrypt_sb_free(s);
put_user_ns(s->s_user_ns);
kfree(s->s_subtype);
call_rcu(&s->rcu, destroy_super_rcu);

20
fs/ubifs/ioctl.c
View file

@ -205,6 +205,21 @@ long ubifs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
#endif
}
case FS_IOC_GET_ENCRYPTION_POLICY_EX:
return fscrypt_ioctl_get_policy_ex(file, (void __user *)arg);
case FS_IOC_ADD_ENCRYPTION_KEY:
return fscrypt_ioctl_add_key(file, (void __user *)arg);
case FS_IOC_REMOVE_ENCRYPTION_KEY:
return fscrypt_ioctl_remove_key(file, (void __user *)arg);
case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
return fscrypt_ioctl_remove_key_all_users(file,
(void __user *)arg);
case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
return fscrypt_ioctl_get_key_status(file, (void __user *)arg);
default:
return -ENOTTY;
}
@ -222,6 +237,11 @@ long ubifs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
break;
case FS_IOC_SET_ENCRYPTION_POLICY:
case FS_IOC_GET_ENCRYPTION_POLICY:
case FS_IOC_GET_ENCRYPTION_POLICY_EX:
case FS_IOC_ADD_ENCRYPTION_KEY:
case FS_IOC_REMOVE_ENCRYPTION_KEY:
case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
break;
default:
return -ENOIOCTLCMD;

11
fs/ubifs/super.c
View file

@ -336,6 +336,16 @@ static int ubifs_write_inode(struct inode *inode, struct writeback_control *wbc)
return err;
}
static int ubifs_drop_inode(struct inode *inode)
{
int drop = generic_drop_inode(inode);
if (!drop)
drop = fscrypt_drop_inode(inode);
return drop;
}
static void ubifs_evict_inode(struct inode *inode)
{
int err;
@ -1925,6 +1935,7 @@ const struct super_operations ubifs_super_operations = {
.destroy_inode = ubifs_destroy_inode,
.put_super = ubifs_put_super,
.write_inode = ubifs_write_inode,
.drop_inode = ubifs_drop_inode,
.evict_inode = ubifs_evict_inode,
.statfs = ubifs_statfs,
.dirty_inode = ubifs_dirty_inode,

226
include/linux/bio-crypt-ctx.h Normal file
View file

@ -0,0 +1,226 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright 2019 Google LLC
*/
#ifndef __LINUX_BIO_CRYPT_CTX_H
#define __LINUX_BIO_CRYPT_CTX_H
enum blk_crypto_mode_num {
BLK_ENCRYPTION_MODE_INVALID = 0,
BLK_ENCRYPTION_MODE_AES_256_XTS = 1,
};
#ifdef CONFIG_BLOCK
#include <linux/blk_types.h>
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
struct bio_crypt_ctx {
int keyslot;
const u8 *raw_key;
enum blk_crypto_mode_num crypto_mode;
u64 data_unit_num;
unsigned int data_unit_size_bits;
/*
* The keyslot manager where the key has been programmed
* with keyslot.
*/
struct keyslot_manager *processing_ksm;
/*
* Copy of the bvec_iter when this bio was submitted.
* We only want to en/decrypt the part of the bio
* as described by the bvec_iter upon submission because
* bio might be split before being resubmitted
*/
struct bvec_iter crypt_iter;
u64 sw_data_unit_num;
};
extern int bio_crypt_clone(struct bio *dst, struct bio *src,
gfp_t gfp_mask);
static inline bool bio_has_crypt_ctx(struct bio *bio)
{
return bio->bi_crypt_context;
}
static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes)
{
if (bio_has_crypt_ctx(bio)) {
bio->bi_crypt_context->data_unit_num +=
bytes >> bio->bi_crypt_context->data_unit_size_bits;
}
}
extern bool bio_crypt_swhandled(struct bio *bio);
static inline bool bio_crypt_has_keyslot(struct bio *bio)
{
return bio->bi_crypt_context->keyslot >= 0;
}
extern int bio_crypt_ctx_init(void);
extern struct bio_crypt_ctx *bio_crypt_alloc_ctx(gfp_t gfp_mask);
extern void bio_crypt_free_ctx(struct bio *bio);
static inline int bio_crypt_set_ctx(struct bio *bio,
const u8 *raw_key,
enum blk_crypto_mode_num crypto_mode,
u64 dun,
unsigned int dun_bits,
gfp_t gfp_mask)
{
struct bio_crypt_ctx *crypt_ctx;
crypt_ctx = bio_crypt_alloc_ctx(gfp_mask);
if (!crypt_ctx)
return -ENOMEM;
crypt_ctx->raw_key = raw_key;
crypt_ctx->data_unit_num = dun;
crypt_ctx->data_unit_size_bits = dun_bits;
crypt_ctx->crypto_mode = crypto_mode;
crypt_ctx->processing_ksm = NULL;
crypt_ctx->keyslot = -1;
bio->bi_crypt_context = crypt_ctx;
return 0;
}
static inline void bio_set_data_unit_num(struct bio *bio, u64 dun)
{
bio->bi_crypt_context->data_unit_num = dun;
}
static inline int bio_crypt_get_keyslot(struct bio *bio)
{
return bio->bi_crypt_context->keyslot;
}
static inline void bio_crypt_set_keyslot(struct bio *bio,
unsigned int keyslot,
struct keyslot_manager *ksm)
{
bio->bi_crypt_context->keyslot = keyslot;
bio->bi_crypt_context->processing_ksm = ksm;
}
extern void bio_crypt_ctx_release_keyslot(struct bio *bio);
extern int bio_crypt_ctx_acquire_keyslot(struct bio *bio,
struct keyslot_manager *ksm);
static inline const u8 *bio_crypt_raw_key(struct bio *bio)
{
return bio->bi_crypt_context->raw_key;
}
static inline enum blk_crypto_mode_num bio_crypto_mode(struct bio *bio)
{
return bio->bi_crypt_context->crypto_mode;
}
static inline u64 bio_crypt_data_unit_num(struct bio *bio)
{
return bio->bi_crypt_context->data_unit_num;
}
static inline u64 bio_crypt_sw_data_unit_num(struct bio *bio)
{
return bio->bi_crypt_context->sw_data_unit_num;
}
extern bool bio_crypt_should_process(struct bio *bio, struct request_queue *q);
extern bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2);
extern bool bio_crypt_ctx_back_mergeable(struct bio *b_1,
unsigned int b1_sectors,
struct bio *b_2);
#else /* CONFIG_BLK_INLINE_ENCRYPTION */
struct keyslot_manager;
static inline int bio_crypt_ctx_init(void)
{
return 0;
}
static inline int bio_crypt_clone(struct bio *dst, struct bio *src,
gfp_t gfp_mask)
{
return 0;
}
static inline void bio_crypt_advance(struct bio *bio,
unsigned int bytes) { }
static inline bool bio_has_crypt_ctx(struct bio *bio)
{
return false;
}
static inline void bio_crypt_free_ctx(struct bio *bio) { }
static inline void bio_crypt_set_ctx(struct bio *bio,
u8 *raw_key,
enum blk_crypto_mode_num crypto_mode,
u64 dun,
unsigned int dun_bits,
gfp_t gfp_mask) { }
static inline bool bio_crypt_swhandled(struct bio *bio)
{
return false;
}
static inline void bio_set_data_unit_num(struct bio *bio, u64 dun) { }
static inline bool bio_crypt_has_keyslot(struct bio *bio)
{
return false;
}
static inline void bio_crypt_set_keyslot(struct bio *bio,
unsigned int keyslot,
struct keyslot_manager *ksm) { }
static inline int bio_crypt_get_keyslot(struct bio *bio)
{
return -1;
}
static inline u8 *bio_crypt_raw_key(struct bio *bio)
{
return NULL;
}
static inline u64 bio_crypt_data_unit_num(struct bio *bio)
{
return 0;
}
static inline bool bio_crypt_should_process(struct bio *bio,
struct request_queue *q)
{
return false;
}
static inline bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2)
{
return true;
}
static inline bool bio_crypt_ctx_back_mergeable(struct bio *b_1,
unsigned int b1_sectors,
struct bio *b_2)
{
return true;
}
#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
#endif /* CONFIG_BLOCK */
#endif /* __LINUX_BIO_CRYPT_CTX_H */

1
include/linux/bio.h
View file

@ -22,6 +22,7 @@
#include <linux/mempool.h>
#include <linux/ioprio.h>
#include <linux/bug.h>
#include <linux/bio-crypt-ctx.h>
#ifdef CONFIG_BLOCK

62
include/linux/blk-crypto.h Normal file
View file

@ -0,0 +1,62 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright 2019 Google LLC
*/
#ifndef __LINUX_BLK_CRYPTO_H
#define __LINUX_BLK_CRYPTO_H
#include <linux/types.h>
#include <linux/bio.h>
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
int blk_crypto_init(void);
int blk_crypto_submit_bio(struct bio **bio_ptr);
bool blk_crypto_endio(struct bio *bio);
int blk_crypto_start_using_mode(enum blk_crypto_mode_num mode_num,
unsigned int data_unit_size,
struct request_queue *q);
int blk_crypto_evict_key(struct request_queue *q, const u8 *key,
enum blk_crypto_mode_num mode,
unsigned int data_unit_size);
#else /* CONFIG_BLK_INLINE_ENCRYPTION */
static inline int blk_crypto_init(void)
{
return 0;
}
static inline int blk_crypto_submit_bio(struct bio **bio_ptr)
{
return 0;
}
static inline bool blk_crypto_endio(struct bio *bio)
{
return true;
}
static inline int
blk_crypto_start_using_mode(enum blk_crypto_mode_num mode_num,
unsigned int data_unit_size,
struct request_queue *q)
{
return -EOPNOTSUPP;
}
static inline int blk_crypto_evict_key(struct request_queue *q, const u8 *key,
enum blk_crypto_mode_num mode,
unsigned int data_unit_size)
{
return 0;
}
#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
#endif /* __LINUX_BLK_CRYPTO_H */

6
include/linux/blk_types.h
View file

@ -18,6 +18,7 @@ struct block_device;
struct io_context;
struct cgroup_subsys_state;
typedef void (bio_end_io_t) (struct bio *);
struct bio_crypt_ctx;
/*
* Block error status values. See block/blk-core:blk_errors for the details.
@ -182,6 +183,11 @@ struct bio {
struct blkcg_gq *bi_blkg;
struct bio_issue bi_issue;
#endif
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
struct bio_crypt_ctx *bi_crypt_context;
#endif
union {
#if defined(CONFIG_BLK_DEV_INTEGRITY)
struct bio_integrity_payload *bi_integrity; /* data integrity */

5
include/linux/blkdev.h
View file

@ -43,6 +43,7 @@ struct pr_ops;
struct rq_qos;
struct blk_queue_stats;
struct blk_stat_callback;
struct keyslot_manager;
#define BLKDEV_MIN_RQ 4
#define BLKDEV_MAX_RQ 128 /* Default maximum */
@ -574,6 +575,10 @@ struct request_queue {
* queue_lock internally, e.g. scsi_request_fn().
*/
unsigned int request_fn_active;
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
/* Inline crypto capabilities */
struct keyslot_manager *ksm;
#endif
unsigned int rq_timeout;
int poll_nsec;

1
include/linux/fs.h
View file

@ -1396,6 +1396,7 @@ struct super_block {
const struct xattr_handler **s_xattr;
#ifdef CONFIG_FS_ENCRYPTION
const struct fscrypt_operations *s_cop;
struct key *s_master_keys; /* master crypto keys in use */
#endif
#ifdef CONFIG_FS_VERITY
const struct fsverity_operations *s_vop;

165
include/linux/fscrypt.h
View file

@ -16,10 +16,10 @@
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <uapi/linux/fscrypt.h>
#define FS_CRYPTO_BLOCK_SIZE 16
struct fscrypt_ctx;
struct fscrypt_info;
struct fscrypt_str {
@ -42,7 +42,7 @@ struct fscrypt_name {
#define fname_len(p) ((p)->disk_name.len)
/* Maximum value for the third parameter of fscrypt_operations.set_context(). */
#define FSCRYPT_SET_CONTEXT_MAX_SIZE 28
#define FSCRYPT_SET_CONTEXT_MAX_SIZE 40
#ifdef CONFIG_FS_ENCRYPTION
/*
@ -61,19 +61,10 @@ struct fscrypt_operations {
bool (*dummy_context)(struct inode *);
bool (*empty_dir)(struct inode *);
unsigned int max_namelen;
bool (*is_encrypted)(struct inode *inode);
};
/* Decryption work */
struct fscrypt_ctx {
union {
struct {
struct bio *bio;
struct work_struct work;
};
struct list_head free_list; /* Free list */
};
u8 flags; /* Flags */
bool (*has_stable_inodes)(struct super_block *sb);
void (*get_ino_and_lblk_bits)(struct super_block *sb,
int *ino_bits_ret, int *lblk_bits_ret);
bool (*inline_crypt_enabled)(struct super_block *sb);
};
static inline bool fscrypt_has_encryption_key(const struct inode *inode)
@ -102,8 +93,6 @@ static inline void fscrypt_handle_d_move(struct dentry *dentry)
/* crypto.c */
extern void fscrypt_enqueue_decrypt_work(struct work_struct *);
extern struct fscrypt_ctx *fscrypt_get_ctx(gfp_t);
extern void fscrypt_release_ctx(struct fscrypt_ctx *);
extern struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
unsigned int len,
@ -135,13 +124,25 @@ extern void fscrypt_free_bounce_page(struct page *bounce_page);
/* policy.c */
extern int fscrypt_ioctl_set_policy(struct file *, const void __user *);
extern int fscrypt_ioctl_get_policy(struct file *, void __user *);
extern int fscrypt_ioctl_get_policy_ex(struct file *, void __user *);
extern int fscrypt_has_permitted_context(struct inode *, struct inode *);
extern int fscrypt_inherit_context(struct inode *, struct inode *,
void *, bool);
/* keyinfo.c */
/* keyring.c */
extern void fscrypt_sb_free(struct super_block *sb);
extern int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
extern int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg);
extern int fscrypt_ioctl_remove_key_all_users(struct file *filp,
void __user *arg);
extern int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
extern int fscrypt_register_key_removal_notifier(struct notifier_block *nb);
extern int fscrypt_unregister_key_removal_notifier(struct notifier_block *nb);
/* keysetup.c */
extern int fscrypt_get_encryption_info(struct inode *);
extern void fscrypt_put_encryption_info(struct inode *);
extern void fscrypt_free_inode(struct inode *);
extern int fscrypt_drop_inode(struct inode *inode);
/* fname.c */
extern int fscrypt_setup_filename(struct inode *, const struct qstr *,
@ -234,8 +235,6 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
/* bio.c */
extern void fscrypt_decrypt_bio(struct bio *);
extern void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx,
struct bio *bio);
extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
unsigned int);
@ -280,16 +279,6 @@ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
{
}
static inline struct fscrypt_ctx *fscrypt_get_ctx(gfp_t gfp_flags)
{
return ERR_PTR(-EOPNOTSUPP);
}
static inline void fscrypt_release_ctx(struct fscrypt_ctx *ctx)
{
return;
}
static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
unsigned int len,
unsigned int offs,
@ -349,6 +338,12 @@ static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
return -EOPNOTSUPP;
}
static inline int fscrypt_ioctl_get_policy_ex(struct file *filp,
void __user *arg)
{
return -EOPNOTSUPP;
}
static inline int fscrypt_has_permitted_context(struct inode *parent,
struct inode *child)
{
@ -362,7 +357,46 @@ static inline int fscrypt_inherit_context(struct inode *parent,
return -EOPNOTSUPP;
}
/* keyinfo.c */
/* keyring.c */
static inline void fscrypt_sb_free(struct super_block *sb)
{
}
static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg)
{
return -EOPNOTSUPP;
}
static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg)
{
return -EOPNOTSUPP;
}
static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp,
void __user *arg)
{
return -EOPNOTSUPP;
}
static inline int fscrypt_ioctl_get_key_status(struct file *filp,
void __user *arg)
{
return -EOPNOTSUPP;
}
static inline int fscrypt_register_key_removal_notifier(
struct notifier_block *nb)
{
return 0;
}
static inline int fscrypt_unregister_key_removal_notifier(
struct notifier_block *nb)
{
return 0;
}
/* keysetup.c */
static inline int fscrypt_get_encryption_info(struct inode *inode)
{
return -EOPNOTSUPP;
@ -377,6 +411,11 @@ static inline void fscrypt_free_inode(struct inode *inode)
{
}
static inline int fscrypt_drop_inode(struct inode *inode)
{
return 0;
}
/* fname.c */
static inline int fscrypt_setup_filename(struct inode *dir,
const struct qstr *iname,
@ -431,11 +470,6 @@ static inline void fscrypt_decrypt_bio(struct bio *bio)
{
}
static inline void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx,
struct bio *bio)
{
}
static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
sector_t pblk, unsigned int len)
{
@ -499,6 +533,65 @@ static inline const char *fscrypt_get_symlink(struct inode *inode,
}
#endif /* !CONFIG_FS_ENCRYPTION */
/* inline_crypt.c */
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
extern bool fscrypt_inode_uses_inline_crypto(const struct inode *inode);
extern bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode);
extern int fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode,
u64 first_lblk, gfp_t gfp_mask);
extern int fscrypt_set_bio_crypt_ctx_bh(struct bio *bio,
const struct buffer_head *first_bh,
gfp_t gfp_mask);
extern bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode,
u64 next_lblk);
extern bool fscrypt_mergeable_bio_bh(struct bio *bio,
const struct buffer_head *next_bh);
#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode)
{
return false;
}
static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
{
return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
}
static inline int fscrypt_set_bio_crypt_ctx(struct bio *bio,
const struct inode *inode,
u64 first_lblk, gfp_t gfp_mask)
{
return 0;
}
static inline int fscrypt_set_bio_crypt_ctx_bh(
struct bio *bio,
const struct buffer_head *first_bh,
gfp_t gfp_mask)
{
return 0;
}
static inline bool fscrypt_mergeable_bio(struct bio *bio,
const struct inode *inode,
u64 next_lblk)
{
return true;
}
static inline bool fscrypt_mergeable_bio_bh(struct bio *bio,
const struct buffer_head *next_bh)
{
return true;
}
#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
/**
* fscrypt_require_key - require an inode's encryption key
* @inode: the inode we need the key for

98
include/linux/keyslot-manager.h Normal file
View file

@ -0,0 +1,98 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright 2019 Google LLC
*/
#include <linux/bio.h>
#ifdef CONFIG_BLOCK
#ifndef __LINUX_KEYSLOT_MANAGER_H
#define __LINUX_KEYSLOT_MANAGER_H
/**
* struct keyslot_mgmt_ll_ops - functions to manage keyslots in hardware
* @keyslot_program: Program the specified key and algorithm into the
* specified slot in the inline encryption hardware.
* @keyslot_evict: Evict key from the specified keyslot in the hardware.
* The key, crypto_mode and data_unit_size are also passed
* down so that e.g. dm layers can evict keys from
* the devices that they map over.
* Returns 0 on success, -errno otherwise.
* @crypto_mode_supported: Check whether a crypto_mode and data_unit_size
* combo is supported.
* @keyslot_find: Returns the slot number that matches the key,
* or -ENOKEY if no match found, or -errno on
* error.
*
* This structure should be provided by storage device drivers when they set up
* a keyslot manager - this structure holds the function ptrs that the keyslot
* manager will use to manipulate keyslots in the hardware.
*/
struct keyslot_mgmt_ll_ops {
int (*keyslot_program)(void *ll_priv_data, const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size,
unsigned int slot);
int (*keyslot_evict)(void *ll_priv_data, const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size,
unsigned int slot);
bool (*crypto_mode_supported)(void *ll_priv_data,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size);
int (*keyslot_find)(void *ll_priv_data, const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size);
};
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
struct keyslot_manager;
extern struct keyslot_manager *keyslot_manager_create(unsigned int num_slots,
const struct keyslot_mgmt_ll_ops *ksm_ops,
void *ll_priv_data);
extern int
keyslot_manager_get_slot_for_key(struct keyslot_manager *ksm,
const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size);
extern void keyslot_manager_get_slot(struct keyslot_manager *ksm,
unsigned int slot);
extern void keyslot_manager_put_slot(struct keyslot_manager *ksm,
unsigned int slot);
extern bool
keyslot_manager_crypto_mode_supported(struct keyslot_manager *ksm,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size);
extern bool
keyslot_manager_rq_crypto_mode_supported(struct request_queue *q,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size);
extern int keyslot_manager_evict_key(struct keyslot_manager *ksm,
const u8 *key,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size);
extern void keyslot_manager_destroy(struct keyslot_manager *ksm);
#else /* CONFIG_BLK_INLINE_ENCRYPTION */
static inline bool
keyslot_manager_rq_crypto_mode_supported(struct request_queue *q,
enum blk_crypto_mode_num crypto_mode,
unsigned int data_unit_size)
{
return false;
}
#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
#endif /* __LINUX_KEYSLOT_MANAGER_H */
#endif /* CONFIG_BLOCK */

54
include/uapi/linux/fs.h
View file

@ -13,6 +13,9 @@
#include <linux/limits.h>
#include <linux/ioctl.h>
#include <linux/types.h>
#ifndef __KERNEL__
#include <linux/fscrypt.h>
#endif
/*
* It's silly to have NR_OPEN bigger than NR_FILE, but you can change
@ -258,57 +261,6 @@ struct fsxattr {
#define FS_IOC_GETFSLABEL _IOR(0x94, 49, char[FSLABEL_MAX])
#define FS_IOC_SETFSLABEL _IOW(0x94, 50, char[FSLABEL_MAX])
/*
* File system encryption support
*/
/* Policy provided via an ioctl on the topmost directory */
#define FS_KEY_DESCRIPTOR_SIZE 8
#define FS_POLICY_FLAGS_PAD_4 0x00
#define FS_POLICY_FLAGS_PAD_8 0x01
#define FS_POLICY_FLAGS_PAD_16 0x02
#define FS_POLICY_FLAGS_PAD_32 0x03
#define FS_POLICY_FLAGS_PAD_MASK 0x03
#define FS_POLICY_FLAG_DIRECT_KEY 0x04 /* use master key directly */
#define FS_POLICY_FLAGS_VALID 0x07
/* Encryption algorithms */
#define FS_ENCRYPTION_MODE_INVALID 0
#define FS_ENCRYPTION_MODE_AES_256_XTS 1
#define FS_ENCRYPTION_MODE_AES_256_GCM 2
#define FS_ENCRYPTION_MODE_AES_256_CBC 3
#define FS_ENCRYPTION_MODE_AES_256_CTS 4
#define FS_ENCRYPTION_MODE_AES_128_CBC 5
#define FS_ENCRYPTION_MODE_AES_128_CTS 6
#define FS_ENCRYPTION_MODE_SPECK128_256_XTS 7 /* Removed, do not use. */
#define FS_ENCRYPTION_MODE_SPECK128_256_CTS 8 /* Removed, do not use. */
#define FS_ENCRYPTION_MODE_ADIANTUM 9
struct fscrypt_policy {
__u8 version;
__u8 contents_encryption_mode;
__u8 filenames_encryption_mode;
__u8 flags;
__u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
};
#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy)
#define FS_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16])
#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy)
/* Parameters for passing an encryption key into the kernel keyring */
#define FS_KEY_DESC_PREFIX "fscrypt:"
#define FS_KEY_DESC_PREFIX_SIZE 8
/* Structure that userspace passes to the kernel keyring */
#define FS_MAX_KEY_SIZE 64
struct fscrypt_key {
__u32 mode;
__u8 raw[FS_MAX_KEY_SIZE];
__u32 size;
};
/*
* Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
*

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/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
* fscrypt user API
*
* These ioctls can be used on filesystems that support fscrypt. See the
* "User API" section of Documentation/filesystems/fscrypt.rst.
*/
#ifndef _UAPI_LINUX_FSCRYPT_H
#define _UAPI_LINUX_FSCRYPT_H
#include <linux/types.h>
/* Encryption policy flags */
#define FSCRYPT_POLICY_FLAGS_PAD_4 0x00
#define FSCRYPT_POLICY_FLAGS_PAD_8 0x01
#define FSCRYPT_POLICY_FLAGS_PAD_16 0x02
#define FSCRYPT_POLICY_FLAGS_PAD_32 0x03
#define FSCRYPT_POLICY_FLAGS_PAD_MASK 0x03
#define FSCRYPT_POLICY_FLAG_DIRECT_KEY 0x04
#define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 0x08
#define FSCRYPT_POLICY_FLAGS_VALID 0x0F
/* Encryption algorithms */
#define FSCRYPT_MODE_AES_256_XTS 1
#define FSCRYPT_MODE_AES_256_CTS 4
#define FSCRYPT_MODE_AES_128_CBC 5
#define FSCRYPT_MODE_AES_128_CTS 6
#define FSCRYPT_MODE_ADIANTUM 9
#define __FSCRYPT_MODE_MAX 9
/*
* Legacy policy version; ad-hoc KDF and no key verification.
* For new encrypted directories, use fscrypt_policy_v2 instead.
*
* Careful: the .version field for this is actually 0, not 1.
*/
#define FSCRYPT_POLICY_V1 0
#define FSCRYPT_KEY_DESCRIPTOR_SIZE 8
struct fscrypt_policy_v1 {
__u8 version;
__u8 contents_encryption_mode;
__u8 filenames_encryption_mode;
__u8 flags;
__u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
};
#define fscrypt_policy fscrypt_policy_v1
/*
* Process-subscribed "logon" key description prefix and payload format.
* Deprecated; prefer FS_IOC_ADD_ENCRYPTION_KEY instead.
*/
#define FSCRYPT_KEY_DESC_PREFIX "fscrypt:"
#define FSCRYPT_KEY_DESC_PREFIX_SIZE 8
#define FSCRYPT_MAX_KEY_SIZE 64
struct fscrypt_key {
__u32 mode;
__u8 raw[FSCRYPT_MAX_KEY_SIZE];
__u32 size;
};
/*
* New policy version with HKDF and key verification (recommended).
*/
#define FSCRYPT_POLICY_V2 2
#define FSCRYPT_KEY_IDENTIFIER_SIZE 16
struct fscrypt_policy_v2 {
__u8 version;
__u8 contents_encryption_mode;
__u8 filenames_encryption_mode;
__u8 flags;
__u8 __reserved[4];
__u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
};
/* Struct passed to FS_IOC_GET_ENCRYPTION_POLICY_EX */
struct fscrypt_get_policy_ex_arg {
__u64 policy_size; /* input/output */
union {
__u8 version;
struct fscrypt_policy_v1 v1;
struct fscrypt_policy_v2 v2;
} policy; /* output */
};
/*
* v1 policy keys are specified by an arbitrary 8-byte key "descriptor",
* matching fscrypt_policy_v1::master_key_descriptor.
*/
#define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR 1
/*
* v2 policy keys are specified by a 16-byte key "identifier" which the kernel
* calculates as a cryptographic hash of the key itself,
* matching fscrypt_policy_v2::master_key_identifier.
*/
#define FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER 2
/*
* Specifies a key, either for v1 or v2 policies. This doesn't contain the
* actual key itself; this is just the "name" of the key.
*/
struct fscrypt_key_specifier {
__u32 type; /* one of FSCRYPT_KEY_SPEC_TYPE_* */
__u32 __reserved;
union {
__u8 __reserved[32]; /* reserve some extra space */
__u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
__u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
} u;
};
/* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */
struct fscrypt_add_key_arg {
struct fscrypt_key_specifier key_spec;
__u32 raw_size;
__u32 __reserved[9];
__u8 raw[];
};
/* Struct passed to FS_IOC_REMOVE_ENCRYPTION_KEY */
struct fscrypt_remove_key_arg {
struct fscrypt_key_specifier key_spec;
#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY 0x00000001
#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS 0x00000002
__u32 removal_status_flags; /* output */
__u32 __reserved[5];
};
/* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */
struct fscrypt_get_key_status_arg {
/* input */
struct fscrypt_key_specifier key_spec;
__u32 __reserved[6];
/* output */
#define FSCRYPT_KEY_STATUS_ABSENT 1
#define FSCRYPT_KEY_STATUS_PRESENT 2
#define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED 3
__u32 status;
#define FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF 0x00000001
__u32 status_flags;
__u32 user_count;
__u32 __out_reserved[13];
};
#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy)
#define FS_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16])
#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy)
#define FS_IOC_GET_ENCRYPTION_POLICY_EX _IOWR('f', 22, __u8[9]) /* size + version */
#define FS_IOC_ADD_ENCRYPTION_KEY _IOWR('f', 23, struct fscrypt_add_key_arg)
#define FS_IOC_REMOVE_ENCRYPTION_KEY _IOWR('f', 24, struct fscrypt_remove_key_arg)
#define FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS _IOWR('f', 25, struct fscrypt_remove_key_arg)
#define FS_IOC_GET_ENCRYPTION_KEY_STATUS _IOWR('f', 26, struct fscrypt_get_key_status_arg)
/**********************************************************************/
/* old names; don't add anything new here! */
#ifndef __KERNEL__
#define FS_KEY_DESCRIPTOR_SIZE FSCRYPT_KEY_DESCRIPTOR_SIZE
#define FS_POLICY_FLAGS_PAD_4 FSCRYPT_POLICY_FLAGS_PAD_4
#define FS_POLICY_FLAGS_PAD_8 FSCRYPT_POLICY_FLAGS_PAD_8
#define FS_POLICY_FLAGS_PAD_16 FSCRYPT_POLICY_FLAGS_PAD_16
#define FS_POLICY_FLAGS_PAD_32 FSCRYPT_POLICY_FLAGS_PAD_32
#define FS_POLICY_FLAGS_PAD_MASK FSCRYPT_POLICY_FLAGS_PAD_MASK
#define FS_POLICY_FLAG_DIRECT_KEY FSCRYPT_POLICY_FLAG_DIRECT_KEY
#define FS_POLICY_FLAGS_VALID FSCRYPT_POLICY_FLAGS_VALID
#define FS_ENCRYPTION_MODE_INVALID 0 /* never used */
#define FS_ENCRYPTION_MODE_AES_256_XTS FSCRYPT_MODE_AES_256_XTS
#define FS_ENCRYPTION_MODE_AES_256_GCM 2 /* never used */
#define FS_ENCRYPTION_MODE_AES_256_CBC 3 /* never used */
#define FS_ENCRYPTION_MODE_AES_256_CTS FSCRYPT_MODE_AES_256_CTS
#define FS_ENCRYPTION_MODE_AES_128_CBC FSCRYPT_MODE_AES_128_CBC
#define FS_ENCRYPTION_MODE_AES_128_CTS FSCRYPT_MODE_AES_128_CTS
#define FS_ENCRYPTION_MODE_SPECK128_256_XTS 7 /* removed */
#define FS_ENCRYPTION_MODE_SPECK128_256_CTS 8 /* removed */
#define FS_ENCRYPTION_MODE_ADIANTUM FSCRYPT_MODE_ADIANTUM
#define FS_KEY_DESC_PREFIX FSCRYPT_KEY_DESC_PREFIX
#define FS_KEY_DESC_PREFIX_SIZE FSCRYPT_KEY_DESC_PREFIX_SIZE
#define FS_MAX_KEY_SIZE FSCRYPT_MAX_KEY_SIZE
#endif /* !__KERNEL__ */
#endif /* _UAPI_LINUX_FSCRYPT_H */